1. The causal agent of tick-borne fever is transmitted by the adult female and the nymphal stage of the tick Ixodes ricinus. Two female ticks are sufficient to produce infection in a sheep. The larval stage does not appear to be infective. In a limited number of experiments the disease has not been produced in sheep by the inoculation of emulsions of presumably infective ticks.

2. The disease as produced by tick infestation is characterised by a period of incubation which varies from 3 to 13 days, after which there is a sharp rise in temperature; a “plateau” type of febrile reaction follows which lasts from 6 to 22 days, the temperature gradually subsiding to normal. Affected animals usually recover. Mortality as a direct result of infection is rare, but there is evidence to suggest that tick-borne fever may predispose affected animals to death from secondary causes.

3. The blood of a sheep which has reacted to the disease remains infective for some time after the subsidence of the thermal reaction.

4. The goat is susceptible to tick-borne fever.

5. The economic importance of tick-borne fever is discussed.

My observations on Lankesteria culicis, as it appears in Aedes albopictus in Calcutta, show that the trophozoites are intracellular in the anterior and extracellular in the posterior regions of the mid-gut, with epimerite rudimentary in the former and well developed in the latter condition. Full-grown forms measure 150–200 × 31–41μ. Association is lateral. Sporocysts measure about 10 × 6μ and are broadly spindle-shaped with slightly flattened ends, with a-residual body situated more toward one pole than the other.

Septate eugregarines in general, excepting the Stenophoridae Léger and Duboscq, grow extracellularly with the epimerite attached to the host cell. Therefore, judging from the foregoing description, we are no longer justified in retaining Lankesteria culicis among the Haplocyte gregarines (Acephalina) and in the family Diplocystidae Bhatia (1930). The presence of a well-developed epimerite and what I consider to be a rudimentary protomerite, clearly distinguish it from any of the Acephalina. Its place should be among the septate gregarines (Cephalina), and perhaps a new genus may have to be erected to receive it there.

The new species herein described, collected by Mr Charles Elton in the course of ecological field work in Norway, was very kindly passed on by him to me for identification and description.

Distomum incommodum (Leidy 1856) from mouth of Alligator mississippiensis is found to belong to the family Clinostomidae. A new genus Homoscaphis Canavan 1933 is erected for it, a diagnosis of which is given, with a redescription and illustration of the species.

Page 124, third line from below (Table I) for “Length of first 4 tarsal segments” read “Length of first tarsal segment.”

The writers (1932) have previously reported on the surprisingly great individual variability in susceptibility to infection with Eimeria miyairii which they encountered among white rats taken at random. It was learned in the study that young rats of from 65 to 149 g. in weight would eliminate from 14 to 169 million oocysts during immunisation produced by inoculation per os with 1500 sporulated oocysts daily over a period of 5 days. The question naturally arises whether different strains of the host exhibit differences in susceptibility similar to those noted in individuals.

The examination of a water moccasin, Agkistrodon piscivorus, caught near Houston, Texas, on May 4th, 1932, revealed five species of parasites, four of which have not been previously reported from this host.

Within the last decade problems dealing with life cycles and relationships of the Strigeid Trematodes have received considerable attention. Among the European workers Szidat (1929, 1929 a) has given the most complete summary of the anatomy, development and systematic position of the Strigeidae, while in North America La Rue (1926), his students and associates, have been contributing to our knowledge of the anatomy, relationships and life histories.

In 1930 Ray published a valuable paper on the genus Selenidium Giard, in which he described sporogony in S. spionis Koll. and S. foliatum Ray. He did not observe schizogony in either of these two, but he confirmed Brasil's account of intracellular schizogony in S. caulleryi Brasil from Protula tubularia Mont, and recorded it for the first time in S. mesnili Brasil from Myxicola infundibulum Mont. After seeing association of gametocytes in both these species he was unable to continue his observations, so I have taken up the work where he left it, choosing S. mesnili rather than S. caulleryi, since it is more easily obtainable. My search for gamete and sporozoite formation has been successful, but I have not been able to make the sporozoites hatch, or in studying sections of Myxicola have I seen sporozoites entering the epithelial cells of the gut.

1. The life histories of Lechriorchis primus Stafford, L. tygarti n.sp. and Caudorchis eurinus n.gen. et sp. have been experimentally completed in three hosts, the first complete life histories to be worked out for species of the subfamily Reniferinae.

2. The definitive hosts of the three forms were found to be two species of garter snakes, Thamnophis sauritus and T. sirtalis.

3. Three species of snails, Physella gyrina, P. parkeri, and P. ancillaria, have been found to serve as the first intermediate host in the life cycles of Lechriorchis primus and Caudorchis eurinus n.gen. et sp., and two species of snails, Physella gyrina and P. heterostropha, in the life cycle of Lechriorchis tygarti n.sp.

4. The tadpoles of two species of frogs, Rana clamitans and R. pipiens, were found to serve as the second intermediate hosts in the life cycles of all three trematodes. The cercariae penetrate larvae of Triturus and small fish, but live only a short time in these animals.

5. Every stage in the life history of Lechriorchis primus, including egg, miracidium, mother sporocyst, daughter sporocyst, cercaria, metacercaria, and developmental stages in the definitive host, has been described in detail.

6. The mother sporocyst of forms having a stylet cercaria is described for the first time.

7. The flame cell pattern of the cercariae of L. primus, L. tygarti n.sp., and Caudorchis eurinus n.gen. et sp. has been determined to be of the “2 × 6 × 3’ type. Also the adult stage of C. eurinus was determined to have the same type.

8. It has been pointed out that the life histories of the members of the subfamily are uniform in that their life history stages display a remarkable similarity.

9. It has been suggested that this uniform type of life cycle and remarkable similarity of larval stages offer the most logical basis for establishing the subfamily Reniferinae as a natural group.

This volume, p. 252, line 16, for “Jajonetta n.g.” read “Ceratotrema n.g.”

Page 186, line 2, for rhodesiense read gambiense.