Notes on the morphology of the Tuniciita. 561 



before the ova are ready for fertilization, and long before the buds 

 are set free from the stolon. 



In addition to the fact of protogyny we observe one other inter- 

 esting feature. The precociously developed testis reaches such a large 

 size that it could hardly be accommodated in the body proper of the 

 small bud without seriously crowding and distorting the development 

 of the organs. But by pushing out into the useless elaeoblast the 

 testis finds a place where it can reach the necessary size without in 

 any way crowding or interfering with the vital organs. 



Salpa cylindrica is, I believe, peculiar among the Salpidae in the 

 l)recocious development of its testis. The testis is actually no larger 

 than it is in many species in which the sperm ripens late, after the 

 chain individuals have increased in size; but, in proportion to the 

 size of the body, the testis of the young chain Salpa cylindrica is 

 much larger than in other species I have studied. This would in- 

 dicate that the observations of the early ripening of the eggs and the 

 delayed maturity of the spermat(jzoa in other species are correct, and 

 that Salpa cylindrica differs in this regard from most species. Study 

 of stolons of different ages from Salpa runcinata-fusiformis shows 

 that in this species the relations are as usually described. In the 

 older stolons of this Salpa, nearly ready to detach from the parent, 

 the testis does not yet appear, nor is it shown in younger stolons. 



I can see no reason why Salpa cylindrica should be protandrous 

 while other species are protogyuous. 



Section IV. 



The Ingestion of Follicle Cells in Lej^toclinum, Salpa 



and the Rat, 



with a suggestion as to the meaning of the seasonal degeneration of 



the upper part of the body in Botrylloides and Leptoclinum. 



Plate 38, Figs. 62—64. 



In this chapter I wish to describe or discuss several things which 

 naturally group themselves together, I have found that Leptoclinum 

 alhidum shows phenomena of seasonal degeneration, somewhat similar 

 to those recently described for Botrylloides by Pizon^). I have also 

 found in the same species interesting differences in the ova and ovaries 



1) PizoN, 1898. 



37* 



