ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 73 



over four times the size of the posterior sucker. It has a muscular rim 

 and five muscular bands. The last segment of the anal region bears 

 ventrally a sensory papilla. There are no eyes. A detailed compari- 

 son is made between CalliohdeUa lophil and this new form. Certain 

 characters are believed by the author to indicate that GanynwleMelJa 

 crater e is a stationary parasite. These are (1) its peculiar attachment 

 to the anal papilla of its host by means of an enormously developed 

 anterior sucker ; (2) the weak development of the longitudinal muscle 

 layer ; (3) the shallowness of the posterior sucker : and (4) the rarity 

 of the leech. 



Nema^tohelminthes. 



Effects of Carbon Dioxide on Eggs of Ascaris.* — Theophilus S. 

 Painter exposed eggs of Ascaris megalocepluiJa to carbon dioxide for 

 three months (July 1-4 to October 9) and afterwards allowed them to 

 develop. Some of the embryos were perfectly normal ; others had only 

 one end of the body developed ; others were totally disorganized. The 

 author shows how the half -embryos and disorganized embryos arise. As 

 to the question why some eggs are affected by the COg treatment while 

 others develop normally, it is pointed out all the eggs were taken from 

 the fresh uterus of a single female, and that those from the end are 

 further advanced than those from the tip. As to the question how the 

 eggs were able to live and develop to a slight degree in an atmosphere 

 of CO2, the author adopts Weinland's view that glycogen in the egg is 

 broken up into valeric acid, CO2, and oxygen. Painter also records 

 some observations bearing on the problems of sex-determination and of 

 cell-diminution. 



Fresh-water Nematodes of Michigan.! — Margaret V. Cobb and 

 N. A. Cobb give an account of some fresh-water Nematodes of the 

 Dottglas Lake region of Michigan, and furnish a very useful key to the 

 genera. Descriptions are given of Tylencholai melius diplodorus g. et sp. n. 

 and new species of Actinolaimus, Dorylaimus, Ironiis, Monondms, 

 CyaUtolaimus, GJiromadora, Ethmolaimus, Aphanolamius, and Prisma- 

 iolaimus. 



Species of Rictularia.J — L. G. Seurat describes some of these 

 Nematodes from the intestine of various carnivores from North Africa 

 (jackal, fox, genet, and mongoose). He deals with Rictularia affinis 

 Jiigersk, R. macdonaldi (Dobson), previously reported from bats, and 

 R. proni sp. n. — the last being marked by the small number of combs and 

 needles, which are restricted to the anterior region ; the position of the 

 post-cervical papillae very far forward ; the shortness of the gullet and 

 the ovijector ; and the structure of the vulva. Some authors place 

 Riciidaria among the Strongylidse, but Seurat maintains that the 

 affinities of the genus (as marked in the structure of the gullet, the 



* Journ. Exper. Zoology, xix. (1915) pp. 355-85 (3 pi?, and 15 figs.). 



+ Trans. Amer. Micr. Soc, xxxiv. (1915) pp. 21-47. 



+ C.R. Soc. Biol. Paris, Ixxviii. (1915) pp. 318-22 (3 figs.). 



