ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 57 



there is considerable discrepancy in regard to the pharynx. The author 

 presents an interesting summary of the data which previous observers 

 have furnished in regard to the correspondence or lack of correspondence 

 between the embryonic and the regenerative development of the pharynx. 

 He is not inclined to draw embryological conclusions from regenerative 

 processes. J. A. T. 



North American Oligochaets. — Paul S. T\^elch {Trans. Amer. 

 Microscop. Soc, 1919, 38, 175-88, 1 pi.). Continuing his studies on 

 Mesenchytrseids, the author gives an account of Mesenchytrseus hydrins 

 sp. n., from an altitude of 3,400 feet on Mount Rainier. The specimens 

 crawled about in sand in slowly moving water, in close proximity to 

 melting snow. The colour is light yellow ; pigmentation is entirely 

 absent. A description of the reproductive system is given. A curious 

 feature is the crossing of the elongated spermothecae. They extend 

 from segment 10 forwards, and at the posterior end of segment 5 or the 

 anterior part of 6, the right organ crosses to the left side of the body 

 and the left organ to the right side. A key is given to the species of 

 Mesenchytrseus known to occur in North America. J. A. T. 



New Echiuroid Genus from Great Barrier Reef.— T. Harvey 

 Johnston and 0. W. Tiegs {Proc. Limi. Soc. N.S.W,, 1919, 44, 

 213-30, 3 pis.). A description of Fseudobonellia Unterina g. etsp. n., 

 an interesting relative of Bonellia, but very distinct. The female shows 

 a Bo7ieUia-\ike form, two to four setaB, two well-developed and func- 

 tional uteri, simple anal glands opening directly into the rectum, an 

 ovary in a posterior transverse position, and a siphon associated with the 

 intestine. There is an invagination or male tube within which a single 

 male is lodged. The male is extremely degenerate and apparently 

 partly fused to the female. It shows two functional vesiculae seminales ; 

 there are no hooks. J. A. T. 



Nematohelminthes. 



Anomaly in Ovary of Ascaris megalocephala. — J. Dragoiu and 

 E. Faure-Fremiet {C.R. Soc. Biol., 1920, 83, 123-5). An adult 

 female, about 20 cm. in length, showed in the ovary no trace of germ- 

 cells. The lumen contained only mucus. It is probable that there had 

 been in the course of development a suppression of the initial cell which 

 gives rise to the germinative line, as contrasted with the somatic lines of 

 the ovarian wall. J. A. T. 



Life-history of Ascaris suilla — F. H. Stewart {Parasitology, 

 1919, 11, 385-7, 1 pi.). Continuing previous investigations, the 

 author reports that after giving about 22,000 ripe eggs of A. suilla 

 to each of two sucking-pigs numerous larvse were found in the small 

 intestine of one (fourteen days after infection), but none in the other 

 (nineteen days after infection). In another case about 50,000 ripe eggs 

 were given, and thirty-one days after no worms were found in the 

 intestine. An account is given of the structure of a larva of A. suilla 

 taken from the intestine of a pig fourteen days after infection. J. A. T. 



