428 PROCEEDINGS OF THE NATIONAL MUSEUM vol. 86 



papilla traversed throughout its length by the tubuiar ejaculatory 

 duct lined by a cuboidal ciliated epithelium. At the penis base, 

 the duct curves ventrally, then turns anteriorly, enlarging into an 

 elongated chamber, the seminal vesicle (fig. 49, ^), called seminal duct 

 by von Graflf (1899), who found a similar condition in Geoplana 

 marginata F. Miiller, 1858. Geopluna caineliae. Fuhrmann, 1914a, also 

 has a seminal vesicle external to the penis papilla, much like that 

 of G. montana. As a rule, the seminal vesicle in planarians is inside 

 the penis bulb, but these species lack a definite penis bulb. The 

 seminal vesicle of G. montana is lined by a ciliated epithelium and 

 in the paratype is surrounded by a halo of eosinophilous glands 

 opening into it; at its anterior end it receives the two vasa deferentia. 

 The female atrium, of elongated-funnel form (fig. 49, Z>), extends 

 posteriorly from the common atrium; it lacks any special muscular 

 thickening and hence is not regarded as a vagina. At its posterior 

 end, the female atrium continues into the glandular duct ("Driisen- 

 gang" of German workers), which curves ventrally as a tube into 

 whose lower end the two oviducts open. Genital atrium lined by a 

 very tall extremely glandular ej^ithelium, particularly well developed 

 in the female atrium, where in the most mature specimen (the para- 

 type) it is thrown into viiluslike folds. Toward the male atrium 

 the epithelium gradually diminishes in height and after turning to 

 cover the penis papilla soon flattens down to the cuboidal epithelium 

 of the latter (fig. 49, c) ; at the genital pore the epithelium is continu- 

 ous with the rhabdite-containing body epithelium, here also very tall. 

 Free ends of atrial epithelium filled with granules (fig. 49, d) stain- 

 ing blue in Mallory's connective tissue stain, hence probably mucous 

 in nature ; their source could not be determined, as no gland cells were 

 seen in the adjacent parenchyma. Outside the atrial epithelium is a 

 somewhat indefinite muscle layer continuous with the parenchymal 

 fibers, best developed in the female atrium and diminishing toward 

 the base of the penis. Glandular duct lined by a tall cokunnar 

 epithelium interspersed with the outlets of the innumerable gland 

 cells, which in the paratype form an immense halo around the duct 

 and also extend into the parencliyma some distance posterior to the 

 duct; gland cells of both cyanophilous and eosinophilous types. 

 Gland cells also accompany the terminal portions of the oviducts. 



Locality. — Type and young immature specimen collected at Coro- 

 nado, Costa Rica, at 1,600 meters, by S. Rafael, April 12, 1935. 

 Paratype collected at Volcan Barba, Costa Rica, at 2,800 meters, by 

 M. Valerio, January 31, 1929. Fourth specimen, in bad condition, 

 considered probably the same species, collected at San Jose, Costa 

 Rica, 1,160 meters, by M. Valerio, no date, probably 1929. 



