436 PROCEEDINGS OF THE NATIONAL MUSEUM vol. 86 



to unite to a common duct before entering the seminal vesicle. Apart 

 from the very muscular seminal vesicle, the male duct is but slightly 

 muscular encircled by sparse circular fibers. It is lined by a low 

 cuboidal epithelium, which is very granular from the beginning of 

 the granule vesicle to the male pore. Between the male and female 

 pores is the small bowl-shaped invagination of the genital sucker 

 lined by a granular epithelium and showing some concentration of 

 dorsoventral parenchymal muscle fibers. The female apparatus, in 

 contrast to that of L. tremellari^^ is very strongly developed. The 

 female pore, situated on an elevation, leads into a large vagina with 

 thick muscular walls, the fibers chiefly circular, and a granular epithe- 

 lial lining. The upper end of the vagina is widened into a large sac- 

 like cavity from the posterior wall of which springs the glandular 

 duct (Kittdriisengang of Bock, 1913). This type of vagina in 

 Bock's terminology would be a bulbous vagina. The glandular duct 

 is a large tube running forward and then backward in the sagittal 

 plane, having thus a V-shape. It is lined by an epithelimn of tall 

 slender cells outside of which there is a considerable muscular in- 

 vestment, mostly of circular fibers witli a few longitudinal ones next 

 the epithelium. The glandular duct receives a tremendous array of 

 long-necked eosinophilous gland cells, which occupy the parenchyma 

 around the whole course of the duct and extend for long distances in 

 all directions. These glands are the shell glands of early authors 

 but are now generally designated cement glands (Kittdriisen) and 

 no doubt secrete the adhesive material in which the eggs are imbedded 

 on laying. At its proximal end the glandular duct receives on its 

 ventral side the very short common uterine duct which almost at 

 once divides into the two uteri; these proceed forward one on each 

 side of the pharynx (fig. 51, a) as wide, thin-walled, coiled canals 

 stuffed with eggs. Behind the entrance of the uterine duct the 

 female canal continues as a duct, which after proceeding postenorly 

 for some little distance widens into a large sac, Lang's vesicle in 

 Bock's terminology. The duct between this vesicle and the entrance 

 of the uterine duct is thus the stalk of Lang's vesicle. In the type 

 species, L. treniellans^ Lang's vesicle is reduced to a slight protu- 

 berance beyond the uterine duct. 



Locality. — Under rock, Mount Doughty, Puget Sound, Wash., col- 

 lected on July 15, 1927, by Everett E. Wehr. 



Type. — Anterior three-fourths as preserved specimen, U.S.N.M. no. 

 20411, including serial sections of postpharyngeal region. 



Remarks. — In his classical revision of the polyclads. Bock (1913) 

 has accepted Lang's opinion that Lepto plana tremellaris (O. F. 

 Miiller, 1774) is the first species to be ascribed to the genus Leptoplana, 

 and the diagnosis of the genus must then be based on L. tremellaris^ 



