REMARKS UPON' APPENDICULARIA AND DOLIOLUM T7 



gill, just anterior to the fourth muscular band ; a narrow oesophagus 

 {K) leads from it into a two-lobed stomach (i) ; from this a narrow 

 intestine passes, and bending a little upwards and then downwards 

 and to the left side, terminates in a papillary (/) anus. Just at its 

 bend the intestine gives attachment to three or four small caeca {/) 

 which appear to represent a liver, and a system of transparent anasto- 

 mosing tubules, similar to that described in Salpa, arises from the 

 stomach and envelopes the intestine in a network. 



The heart if) lies above and in front of the mouth. In structure it 

 resembles that of Salpa. There are no vessels of any kind, the blood- 

 corpuscles making their way at random among the viscera. No 

 reversal of the circulation was observed in this Ascidian. 



94. All the specimens examined possessed only the male generative 

 apparatus, in the shape of a long tubular ^ testis (/>), placed on the 

 right side and below, and opening posteriorly into the respiratory 

 chamber by a papillary elevation (/') just before the penultimate 

 muscular band. 



The testis lies quite freely in the sinus, and is bathed by the blood 



(fig- 7). 



When most fully developed the testis nearly equals the body in 

 length ; but in young specimens it may be not more than one-half 

 to one-third that size. 



The young testis is a delicate sac, containing a mass of circular 

 cells, about -j-sVoth of an inch in diameter, of a pale greenish colour, 

 and flattened. 



As development proceeds, these cells assume a redder tint, and be- 

 come perfect spermatozoa with elongated cylindrical heads -g-g-Voth of 

 an inch in length, and very delicate, long filiform tails. 



95. There is a small cavity («) resembling the ciliated fossa of the 

 Salp(2, seated upon the anterior face of the singular process of the 

 ventral paries of the respiratory cavity. 



This process lies anterior to the first muscular band ; it is somewhat 

 conical and excavated behind. The two lips of the excavation are 

 thickened and ciliated, and the right lip is continuous on the left side 

 with a ciliated band, which runs up parallel with the first muscular 

 band, passes over to the right side, and running down, becomes even- 

 tually lost in the right portion of the base of the conical process. 



This would seem to be a rudimentary languet. A number of small 

 granular masses were always to be seen attached to the inner tunic 

 close to the posterior aperture. 



The structure of the branchiae of this Ascidian, the position of the 



1 Very similar to that of Salpa cristata, described as an hepatic organ by Meyen. 



