478 PROCEEDINGS OF THE ACADEMY OF [Sept., 



across the mid line, they extend forward skirting the gut as un- 

 branched, swollen chambers often filled with a comparatively large 

 number of ova. Opposite the posterior end of the pharyngeal 

 pocket they bend inward and unite under the base of the pharynx. 

 The resulting median duct is short and proceeds anteriorly and 

 ventrally to the ample shell chamber which receives the ductules 

 from many filiform glands (PL XVIII, fig. 37). Ventral to this 

 point is the moderate antrum which opens to the exterior ventral 

 to the base of the pharynx. Dorsal to the shell chamber a small 

 zone of glandular tissue, staining darkly in Delafield's hematoxylin, 

 surrounds the egg canal. What its function is it is impossible to 

 determine. No uterus glands were observed in any of the whole 

 mounts or sections, though considerable pains were taken to deter- 

 mine this point. 



Genus ACEROS Long, 1884. 



Body smooth. Mouth immediately behind the brain. Pharynx 

 cylindrical. About 5 pairs of gut branches. Male sex pore imme- 

 diately behind the mouth; female near hinder end of pharyngeal 

 pouch. Tentacles lacking. 



Aceros langi sp. nov. 



A single representative of this species was taken on the southern 

 shore of Monterey Bay, but concerning its habits or habitat we are 

 without information. Its form in life was probably elliptical and 

 measures 8 mm. in length by 6 in width. The ventral sucker 

 (PI. XII, fig. 5) is slightly posterior to the middle of the body. The 

 anterior margin of the animal was slightly injured which prevents 

 the precise determination of the exact location of the mouth with 



reference to it. However, the mouth 



may safely be said to be very close 



to the anterior end of the bod v. 



/- _ The penis is directed forward. 



t ' There are no nuchal tentacles; 



+ % • marginal tentacles may have existed 



-# *** " • *•*• on the damaged portion, though no 



% * "" •• b ' trace of them now remains. About 



• •• 



• *• • •" fifty large eyes (text fig. 6) overlie 



*• * the brain area that are roughly 



divided into two irregular clusters. 

 -Eyes of Aceros langi. No eyes have been seen on other 



regions of the body. 

 The mouth (PI. XVII, fig. 38) opens into the cylindrical pharyn- 



