462 PROCEEDINGS OF THE ACADEMY OF [Sept., 



The brain, about one-fourth the length of the body from the 

 anterior end of the animal, is oblong in transverse diameter, slightly 

 emarginate in front and behind, and gives rise to atrleast four pairs 

 of lateral nerve trunks. Over most of the body the larger nerve 

 trunks have been traced with unusual distinctness, and the results 

 show that the nervous system in general conforms to the usual type. 



The testes are ventral, and especially in an immature state their 

 arrangement suggests that they are united by sperm canals, forming 

 an anastomosing system, though, generally speaking, these capillaries 

 are invisible. The vasa deferentia, on each side of the body, form 

 a narrow, inverted-U-shaped loop whose distal end arises abreast of 

 the male aperture, the bend occurring opposite the mouth. Owing 

 to the rather poor preservation of the specimens, the details of the 

 male reproductive apparatus could not be determined completely. 

 The proximal ends of the vasa deferentia appear to terminate in 

 what seems to be a large antrum masculinum (PI. XVIII, fig. 44), 

 but no seminal vesicle could be seen nor could the penis be clearly 

 studied, although it is doubtless directed backward. The male sex 

 opening is well removed from the pharyngeal pocket. 



The ovaries are dorsal, and an anastomosing connecting system 

 of oviducts exists. The uteri extend forward, running parallel to 

 the inner limbs of the vasa deferentia, and thus pursue a course 

 directly forward to the tentacles to terminate immediately behind 

 them. Posteriorly, these canals pass dorsal to the vasa deferentia, 

 and lateral to the male aperture where they bend quickly inward 

 toward the median line. As in the case of the male reproductive 

 system, the details of the female reproductive complex could not be 

 ascertained with certainty. The uteri appear to lead directly into a 

 large antrum femininum, but there are also indications of an accessory 

 gland, though its relations were not established satisfactorily. The 

 female sex opening is immediately behind that of the male system. 



Two peculiar deep pits (PL XVIII, fig. 44, dp), one immediately 

 in front of the level of the male aperture and one immediately behind 

 the female aperture, occur on the dorsal surface connected by a 

 narrow, shallow groove. This appears in two of the largest indi- 

 viduals, but there is no clue to their function. 



Named in memory of Mr. Samuel Burcham, who undertook the 

 investigation of the polyclads of the California coast while a student 

 at Stanford University. This work, still in its early stages, was 

 terminated by his untimely death. 



