POLYCLADS OF THE ATLANTIC COAST — HYMAN 457 



cllipsoides came, is labeled L. ellipsoides, also identified by Verrill. 

 This specimen is identical with the one labeled T. folium but is imma- 

 ture. The only other species from the Bay of Fundy that might be 

 Leptoplatia eUipsoides is Notoplana atomnata. Bock, indeed, is of the 

 opinion (1913) that Leptoplana eUipsoides is a synonym of Noto- 

 plwiu atotnata^ but he bases this decision on Verrill's figures (189!^ 

 93) labeled Leptoplmw. eUipsoides. Now I agree with Bock that 

 these figures of Verrill's are really Notoplana atomata^ but I think 

 that Verrill's identification is erroneous. N. atomata and L. eUip- 

 soides cannot possibly be identical, to my mind. First, the most 

 definite character of L. eUipsoides in the original description is that 

 the animal is elliptical, with pointed anterior end, whereas N. ato- 

 mata is obovate with broad rounded anterior end. Second, it is 

 stated by Girard that L. eUipsoides swims ; N. atomata never swims. 

 I am therefore confident that L. eUipsoides is not a synonym of N. 

 atomata but that it is identical with Trigonoporus folium. The 

 investigation of the best of the four specimens mentioned above, 

 namely, the whole mount No. 15621, labeled Trlgonoponis folium^ 

 has shown that the animal is not a TAgonoporus at all but fits best 

 into the genus Discocelides. It differs from the only other known 

 species of the genus, D. langi^ described by Bock (1913) in that 

 there is no connection between the vagina and the stalk of Lang's 

 vesicle. Bock made the presence of this short duct a generic char- 

 acter, but it seems best to me to omit it from the generic definition 

 in order to include eUipsoides in the genus. The present species is 

 certainly closer to D. langi than it is to PleJinia., the only other 

 genus of the Plehniidae. In Plehnia the prostate has a very thick 

 muscular wall occupying the greater part of the organ and a small 

 glandular interior, and Lang's vesicle is short and rounded. 



Family LATOCESTIDAE Laidlaw, 1903 



Definition. — Craspedomjnata with slender elongate bodies ; tentacles 

 absent ; brain and anterior end strewn with numerous small eyes, not 

 grouped into clusters; prostate vesicle free; seminal vesicle absent; 

 penis unarmed. 



Genus LATOCESTUS Plehn, 1896 



Oculoplana Pkabse, 1938. 



Definition. — ^Latocestidae with pharynx near the posterior end, 

 hence with a very long main gut from pharynx to anterior end ; copu- 

 latory apparatus behind pharynx very close to posterior end ; genital 

 pores separate; Lang's vesicle present. 



251544 — 40 2 



