Notes on the morphology of the Tunicata. 559 



parently nerve fibres, running out from the opposite (basal) ends of 

 these cells seem to indicate that they are sensory cells. As mentioned 

 in Section I of this paper, the upper end of the ciliated funnel of 

 Salpa cylindrica has an epithelium of cubical, non-ciliated cells and 

 to these cells a nerve can be traced. It is significant to find in 

 another species that the cells occupying a similar position have a 

 structure that suggests a probable sensory nature. 



A somewhat puzzling peculiarity is seen in one of the two cells shown 

 in Fig, 89 S. Two fibres arise from this cell, one looking as much 

 like a true nerve process as the other. This is the only case in which 

 such a condition was seen. Careful study under high magnification has 

 shown, beyond doubt, that both processes are actually connected with 

 this one cell. 



From these observations upon the histology of the ciliated funnel, 

 as well as from my studies of the innervation of the funnel in other 

 species of Salpa and other Tunicates, there seems no room for doubt 

 of the sensory nature of the funnel. It is, however, Hunter's ob- 

 servations upon material treated with methyl blue that clinch this 

 evidence, establishing, so far as anatomical observations can, the 

 sensory nature of this organ. I have previously shown (Section I, 

 page 552) that innervating fibres run to both the ciliated epithelium of 

 the funnel and to the non-ciliated epithelium of the duct of the neural 

 gland, near its point of connection with the funnel. In lasis one 

 finds cells, whose form seems to indicate a sensory nature, both among 

 the ciliated cells of the funnel and among the non-ciliated cells lining 

 the upper part of the funnel. The latter non-ciliated epithelium 

 seems to correspond to the non-ciliated cubical epithelium which in 

 Ascidians lines the distal part of the duct opening into the funnel. 



Section III. 



Protaiidry m Salpa cylindrica Cuv. ^). 



Plate 38, Fig. 61. 



The class Tunicata is composed of hermaphrodite animals in 

 which, without exception, so far as heretofore reported, the eggs 

 mature before the spermatozoa. In the Salpidae we find this proto- 

 gyny most clearly shown. The solitary Salpa has in the ventral part 



1) Cf. Metcalf, 18952, V. 



Zool, Jahrb. XIII. Abth. f. Morph. 37 



