68 CALIFORNIA ACADEMY OF SCIENCES. 



also their nuclei, and the protoplasm is recognizably 

 granular (fig. 16^, pi. iii g- c.) I have no sufficient reason 

 either for or against the supposition that these are hepatic 

 cells. They are apparently quite different from what 

 have been regarded as cells of this kind in many other 

 Tunicates. Maurice ('88, p. 178), considers Milne-Ed- 

 wards in error in regarding the " ventricule chylifique " 

 as being glandular, and he states that in Fragroides the 

 epithelium lining it is the same as that lining the oesopha- 

 gus. Such is certainly not the case in Perophora. The 

 cells are not ciliated as in the oesophagus. They are, 

 also, considerably higher here than there, and as far back 

 toward the rectum as the folds which lead to the cosca 

 extend, pellicles of secretive matter are abundant on their 

 inner ends. It appears to me that this part of the diges- 

 tive tube, including the caeca, is undoubtedly secretory, 

 and that exclusively. 



The walls of the whole rectal portion of the intestine, 

 including the posterior part of the region over which the 

 " organe refringent " of Girard ramifies, is composed of 

 a single layer of rather low epithehal cells which are 

 ciliated, but do not have the cuticula characteristic of 

 the cells of the duodenum. They are quite uniform in 

 size and structure and do not appear to be secretory in 

 function, excepting in a region that is transitional from 

 the ch3dific vesicle. It seems to me probable that this is 

 pre-eminently the absorptive portion of the digestive tract. 

 In contradistinction to what is known to be the case in 

 many other Tunicates, I am unable to find muscle fibers 

 in any portion of the digestive tract. This agrees with 

 Kowalevsky's ('74, p. 17), observations on P. Listeri. 



In his description of the "organe refringent" or 

 "pyloric gland," Chandelon ('75, p. 922), says that the 

 " ramifications sont maintenues en place par une mem- 



