146 WALTER GARSTANG, M.A. 



Dorsal tubercle circular in shape ; aperture horse-shoe shaped, the 

 right horn curved inwards. 



Epipharyngeal groove considerably longer, its lips gradually narrowing 

 and becoming continuous with the dorsal lamina. 



In all other respects this individual agrees with the former. 



Both individuals are mature and have ova and spermatozoa in their 

 generative ducts, 



I believe that in point of size these specimens have undergone a 

 considerable reduction since their capture. In the rough notes which 

 I then made, I put down the length as " about 5 inches," while 

 actual measurement now shows that the largest of the two brought 

 away does not exceed 3 inches. Allowing for a possible degree of 

 error in my original estimate of their size, there must still, I think, 

 have taken place some contraction of their test and body in the four 

 months during which they have been in alcohol. It is, I admit, unsafe 

 to argue upon these grounds, for the larger ones may have been just 

 those which I dissected at the time of capture and did not retain. 

 I will, therefore, merely state that the size of some of the specimens 

 which I found was fully 4 inches. 



The colour of the individuals when alive was hardly different from 

 that which these spirit specimens now exhibit. It is sufficient to say 

 that there was an almost total absence of red pigment in their bodies, 

 and what did exist was confined to the region of the siphons, par- 

 ticularly the oral siphon. The test-vessels, also, with their terminal 

 dilatations, were destitute of red and of all conspicuous colouration. 



The species Ascidia mentula has been described in greatest detail 

 upon Mediterranean specimens, although it is widely distributed round 

 all the coasts of Europe, and has been called the commonest of the 

 British deep-water Ascidians. Off the south-western shores of England, 

 however it is certainly not common within the 40 fathom line ; I have 

 only taken it once or twice there, and its place seems to be occupied by 

 two other large Ascidians, Phallusia mammillata and a course variety 

 of Ascidiella aspersa. Indeed, the fact that there is extant no anato- 

 mical description of British specimens referred to Midler's species, 

 seems at first strange, if they are really so abundant. A comparison 

 of my specimens with Miiller's original description revealed some 

 distinctions which at the outset seemed to be of some importance. 



