POLYCLADS OF THE ATLANTIC COAST — HYMAN 459 



Remarks. — Pearse failed to understand this species, placing it in 

 the wrong section and family of the Polycladida; his genus Ocido- 

 flana becomes a synonym of Latoceatus. The species is a typical 

 Latocestus^ agreeing with other members of the genus in the details 

 of its anatomy. It is the first Latocestus to be found on the shores 

 of North America. 



Family STYLOCHIDAE Stimpson, 1857 (emend. Bock) 



Def/nition. — Craspedommata with more or less elongate oval to 

 oblong bodies of thick opaque texture ; with a pair of nuchal tentacles 

 containing eyes; cerebral and often frontal eyes also present; pharynx 

 richly ruffled ; copulatory complex in posterior body fourth ; prostatic 

 vesicle free ; with true or accessory seminal vesicles. 



Genus STYLOCHUS Ehrenberg, 1831 



Imagine Gikakd, 1853. 

 Eustylochus Verrux, 1892. 



Definition. — Stylochidae with well-developed retractile tentacles; 

 genital pores close together; true seminal vesicle, often tripartite; 

 prostatic vesicle large; vagina simple, short; no Lang's vesicle. 



STYLOCHUS ELLIPTICUS (Girard, 1850) 

 FiGUKE 25, C 



Planocera elUptica Gieabd, 1850, p. 251. 



Planocera nehulosa Girard, 1853, p. 367. 



Stylochopsis Httoralis VfeRRiLL. 1873, p. 632, pi. 19, fig. 99. 



Stylochus Httoralis Lang, 1884, p. 453.— Meixnehi, 1907, p. 428, pi. 27, fig. 8. 



EuKtylochus elUpticus Verrill, 1892, p. 467, pi. 40, fig. 2 ; pi. 41, figs. 1, la ; pi. 42, 



figs. 1, la.— Pearse, 1938, p. 73. 

 Eustylochus meridionalis Pearse, 1938, p. 73, fig. 25. 

 Stylochus elUpticus Htman, 1939a, p. 130, figs. 2, 3. 



Material. — Many slides of Pearse labeled Eiistylochus meridionalis., 

 some labeled EiistyTochu.s eUi-ptiGus., several unidentified vials in U. S. 

 National Museum collection. 



Foi^m. — Oval, more or less elongate, flat, thick, with thinner mar- 

 gins, maximum length 20-25 mm., with a pair of tentacles at the 

 level of the brain, elongate and pointed in life, often retracted to a 

 rounded shape in preserved specimens. For general appearance see 

 Hyman, 1939a, fig. 2, p. 133, and Pearse, 1938, fig. 25. 



Eyes. — Marginal band of eyes limited to anterior third or half of 

 the body; in some specimens scattered eyes smaller than those along 

 the anterior margin may occur along rest of body margin. Tentacles 

 filled with eyes; cerebral and frontal eyes not distinctly separable, 



