200 SUiVniARY OF CURRENT RESEARCHES RELATING TO 



lateral margin ; three longitudinal muscle layers alternate with three 

 transverse layers. The testes are numerous, in a double row, occupying 

 the centre of the proglottis, and extending laterally beyond the excretory 

 canals. The yolk-gland is compact and posterior to the ovary; the 

 receptaculum is spherical ; the ovary is strongly lobed ; there is no per- 

 sistent uterus ; the eggs have three membranes ; they are enclosed in 

 parenchymatous capsules, each containing several eggs. The spermato- 

 genesis is described. 



Notes on Parasitic Worms found in Fishes.*— Edwin Linton 

 has taken a wide survey, and finds no evidence of any marked seasonal 

 periodicity in the occurrence of helminth parasites in fishes. Incident- 

 ally he refers to some other points. Nematodes, occasionally seen in 

 the flesh of fishes, are likely to be destroyed in cooking, and are not 

 likely in any case to find a suitable host in man. Cysts of a Cestode, 

 Otobothrium crenacolle, are not infrequent in the flesh of the butter- 

 fish, Poronotus iriacanthus, and the adults are found in the spiral valve 

 of the hammerhead shark and related forms. 



Larval Trematodes in Marine Molluscs.f — Edwin Linton examined 

 numerous difi^ereut species of molluscs at A\'oods Hole, but found larval 

 Trematodes only in two cases. In Ilyanassa obsoJeta and in Pecten 

 imtdUms there were sporocysts and cercariffi, which are described. A 

 few cysts were found in the edible mussel. The author notes that the 

 redia stage is omitted from the larval stages of Trematode develop- 

 ment which he has observed in the Invertebrates at Woods Hole, and 

 he calls attention also to the abbreviation of life-history in the Distome, 

 Parorchis avitus, from the herring gull, where miracidia, still within 

 the ova in the uterus, contained each a single well-developed redia. 



Comparative Anatomy of Anoplocephalidse.l — H. Douthitt gives 

 the result of his investigations towards a comparative anatomical study 

 of the Cestode family of the Anoplocephalida?. The paper consists 

 mainly of descriptions of individual genera and species, but certain 

 general conclusions have been arrived at. The Cestodes of the sub- 

 family Anoplocephalinge are in some way dependent on rich soils for 

 their existence, and they thrive best in wet lowlands. The evidence 

 points to the conclusion that the intermediate hosts are insects confined 

 to such regions : and since the hosts of the Anoplocephalidfe are almost 

 exclusively herbivorous, it would seem probable that this host is a small 

 insect feeding on plants. The primitive Auoplocephaline uterus was of 

 the reticulate type, which in turn was derived from a median longi- 

 tudinal tubular uterus by lateral outgrowths. The transverse tubular 

 and diffuse uteri of this group have been derived from the reticular 

 by simplification. In the early primitive Anoplocephalidse the uterus 

 crossed the excretory ducts ventrally ; subsequently it became restricted 

 to the median field, and later came to cross the excretory ducts dorsally. 

 The position of the vaginal pore and vagina is one of the most stable 



* Trans. Amer. Fisheries Soc, 1914, pp. 48-56. 



t Biol. BuUetin, xxviii. (1915) pp. 198-209 (8 figs.). 



J Illinois Biol. Monographs, i. (1915) pp. 5-96 (6 pis.). 



