Iksookimia longicorpa and Cobitis hankugensis are two species of fish distributed only on the Korean Peninsula. They have a unique reproductive ecology that naturally hybridizes into three widely known unisexual types, maintaining populations of almost all females. In this study, the fine structure of the micropyles of I. longicorpa, C. hankugensis and their hybrids was analyzed to find out how egg–sperm interaction, a common interspecies isolation mechanism, is possible between heterogeneous species. Analysis of 30 eggs from five females of each species revealed that all had one funnel-shaped micropylar region and a manhole-shaped micropyle canal. With the exception of C. hankugensis, which had no spiral grooves or ridges, the rest had counterclockwise spiral grooves and ridges on the micropylar region. All five species, however, showed identical groove patterns for the micropyle canal. The egg size was the largest in HL (one from the C. hankugensis locus with one from the I. longicorpa locus) and the smallest in C. hankugensis. In the hybrids, the HL type had the largest egg and HHL (two from the C. hankugensis locus with one from the I. longicorpa locus) type the smallest. For the diameter of the micropylar region and micropyle canal, the diploid I. longicorpa, C. hankugensis and HL were smaller than those of the triploid. In addition, as the ratio of the canal diameter to the eggs was lower in I. longicorpa than in C. hankugensis, it was confirmed that I. longicorpa has a relatively small micropyle canal compared with C. hankugensis.

We present recent evolutions of the detailed opacity code SCO-RCG which combines statistical modelings of levels and lines with fine-structure calculations. The code now includes the Partially Resolved Transition Array model, which allows one to replace a complex transition array by a small-scale detailed calculation preserving energy and variance of the genuine transition array and yielding improved higher-order moments. An approximate method for studying the impact of strong magnetic field on opacity and emissivity was also recently implemented. The Zeeman line profile is modeled by fourth-order Gram-Charlier expansion series, which is a Gaussian multiplied by a linear combination of Hermite polynomials. Electron collisional line broadening is often modeled by a Lorentzian function and one has to calculate the convolution of a Lorentzian with Gram-Charlier distribution for a huge number of spectral lines. Since the numerical cost of the direct convolution would be prohibitive, we propose, to obtain the resulting profile, a fast and precise algorithm, relying on a representation of the Gaussian by cubic splines.

In the absence of Woodin cardinals, fine structural inner models for mild large cardinal hypotheses admit forcing extensions where bounded forcing axioms hold and yet the reals are projectively well-ordered.

The eggshell fine structure of a lepidopteran pest of mulberry, Amata passalis F. (Lepidoptera: Amatidae), was investigated using scanning electron microscopy. The micropylar rosette around the micropyle, shell imprints, aeropyles and regional differentiation were studied. The surface of the amatid eggshell had a highly decorated chorion with structural difference at the anterior and posterior poles. The micropylar structure was at the anterior pole of the spherical eggs (488 ± 0.595 mm in diameter), opposite to its side of attachment to the substratum. The micropylar rosette measured 51.20 ± 0.52 mm in diameter and was formed of 15–19 petal-shaped primary cells. The micropylar opening into the micropylar canal was 3.76 ± 0.52 mm in diameter. The entire surface of the chorion had a reticulate pattern of pentagonal and hexagonal cells, each of which was boarded by 3 to 6 aeropyles of similar size (0.36 ± 0.008 mm in diameter).

The aim of the present study was to investigate the ultrastructure of secretory cells in the various regions of the goat oviduct during the follicular and luteal phases of the oestrous cycle. During the follicular phase in the fimbriae, the secretory cells contained small secretory granules with electron-dense matrices. In the luteal phase, the secretory granules disappeared and cytoplasmic protrusions, extending beyond the luminal border of the ciliated cells and often containing the nucleus, were predominant. During the follicular phase in ampullary secretory cells, numerous secretory granules with moderately electron-dense matrices were present in the supranuclear cytoplasm and exocytosis of secretory granules was observed. The number of secretory granules was dramatically reduced in the ampullary secretory cells at the luteal phase. Conspicuous cytoplasmic protrusions of secretory cells were observed similar to those of the fimbrial epithelium. Isthmic cells were almost free of secretory granules and lysosome-like bodies were found both at the follicular and luteal phases. In conclusion, our ultrastructural observations of goat oviduct revealed marked cyclic changes in the ultrastructural features of secretory cells and the ultrastructural features and the numbers of secretory granules were distinctive for each particular segment.

Light and electron microscopy were used to study the ultrastructure of the cement apparatus, namely cement glands and cement ducts of mature specimens of the acanthocephalan parasite Pomphorhynchus laevis Müller, 1776, recovered from the digestive tracts of fish Leuciscus cephalus Risso, 1826. In addition, the cement glands of immature P. laevis found within the body cavity of the fish Alburnus alburnus alborella De Filippi, 1844 were examined. In a mature male of P. laevis the 6 cement glands are rounded to oval in shape and each of them has an outer cytoplasmic layer containing nuclei and surrounding a space for storage of the cement material within the gland. The nuclei have an irregular outline and the cytoplasm of the cells contains round, membrane-bound secretory granules approximately 1 μm in diameter. Nuclei surrounded by secretory granules were present inside the gland lumen. Within the gland ducts of mature males, granules were present within the wall thickness and, inside the luminal area, mitochondria were encountered. In contrast, within the cement glands of immature P. laevis there were no secretory granules and the chromatin of the nuclei appeared condensed. The nature of the secretory product of the cement glands was investigated with histological and electrophoretic methods. A protein with molecular weight of 23 kDa was recorded as a major component of cement.

The formation of the definitive procercoid excretory system of the pseudophyllidean cestode Triaenophorus nodulosus has been investigated. This process can be divided into 3 main stages. In the first stage, active autophagic processes lead to the formation of intracellular excretory canals. In the second stage, the process of the autolysis is enhanced and the system of intercellular lacunae functioning as an excretory system is formed. A definitive excretory system of the procercoid forms at the next stage, by means of the migration and proliferation of undifferentiated cells replacing the lacunar system.

A Crypthecodinium cohnii-like dinoflagellate was found to prey on the unicellular red alga Porphyridium sp. The cytoplasm of the prey is ingested by myzocytosis within 10–30 s, and the contents of up to 20 Porphyridium cells can be taken up by one dinoflagellate. The feeding tube is retracted after each uptake process. Cytochalasin D disturbs the suction and the retraction of the feeding tube. Feeding behaviour depends on the light–dark regime: the dinoflagellates prey preferentially in the dark period and finish the trophic phase at the beginning of the light period. They then assemble and encyst, and digestion takes place in the light period. Cell division is restricted to the encysted stage. At the end of the light period excystment takes place, combined with defecation. Isogamy as well as anisogamy and nuclear cyclosis were observed. The trophonts have very thin thecal plates and a microtubular basket with two kinds of elongate vesicles. The microtubules of the tubular basket are also found in young cysts, formed after the end of the feeding period. The fine structure of the digestion vacuoles and of the faecal bodies is described.

The morphology of the sensilla sensitive to vertebrate host-associated stimuli is diverse reflecting the numerous independent origins of haematophagy within the insects. Using electron microscopic techniques, the sensilla of mosquitoes and blackflies have been the most thoroughly studied, although numerous works have been conducted on other blood-feeders. Notably lacking are fine structure studies on blood-feeding maggots and ectoparasitic, adult Muscomorpha.

In comparing blood-feeders with other insects it becomes apparent that: (1) carbon dioxide plays a significantly greater role in location of food by haematophagous insects than by phytophagous and saprophagous species; (2) only in blood-feeders do the adenosine phosphate nucleotides, a single group of compounds, appear to be the phagostimulants for almost all species; and (3) feeding deterrents are unknown in haematophagous insects.

When the sensory complements of the various groups of blood-feeders are compared, three points emerge. First, reduction in numbers of olfactory chemosensilla that mediate odour cues used in long-distance, host-orientation occurs in male nematocerans and in females of completely autogenous species of mosquitoes and black flies. Second, there is a striking correlation between the number of labial chemo- and mechanosensilla and the feeding behaviour of the insect. Third, there is a possible positive correlation between the number of chemosensitive antennal neurones and the distance travelled by the insect to the host.

Living Crustacea possess many types of sensory receptors that detect environmental signals. These structures allow the speculation that similar organs existed in fossil arthropods and were involved in similar ways in the fossil forms when they were extant.

Posture, for example, is difficult to reconstruct in fossils without the understanding that internal proprioceptors monitoring position and movement are crucial in determining the placement of limbs, and the position of the abdomen and other jointed portions of the body. These receptors are associated also with autotomy reflexes through soft cuticle detectors that respond to strain not associated with joints.

Many receptors are placed on the outer surface of the animal, the eyes being the most obvious. The eyes receive no attention in this paper, but descriptions are given of a number of different types of setae, serving both mechanical and chemical sensors. The possession of a pore at the apex (or sub-apex) of a seta or setule probably indicates a chemoreceptor function, but its absence does not necessarily indicate a lack of such sensitivity. A range of forms is illustrated.

The dorsal organ is a recently discovered structure in decapod larvae. It is composed of a central single gland cell opening via an aperture in the midline just behind the rostrum. It is bounded by four depressions each containing a central ‘nipple’. These prove to be sensors, with ciliated endings (bifid) that end in a highly modified cuticle at the depression nipple. The function is unknown, but it is proposed that it represents an unusual chemoreceptor.