116 1UMTLSH TUXICATA. 



irregularly tuberculated. The tubercle in front of the 

 oral lamina is small and horse-shoe-like, with the 

 extremities rounded and turned upwards. ,The ten- 

 tacular points at the left side of the mouth, and those 

 in continuation of the oral lamina downwards on the 

 other side, are few and very large. The tentacular 

 filaments are arranged in a widish, crowded collar, in 

 which they are small in front, and lono- and slender 



t/ o 



behind. 



The principal portion of the ovary is spread over 

 the left side of the intestine ; there are a few branches, 

 however, at the upper part of the loop on the right 

 side. It is composed of numerous, irregular, and 

 somewhat confused ramifications of no great size. 

 Male caeca appear on both sides of the alimentary tube, 

 but are most numerous at the right side, where they 

 extend to the stomach, over which there is a coating 

 of large cells. 



This species comes nearest to A. depressa, but is less 

 depressed, less loosely attached, and without the mar- 

 ginal disc dividing the upper from the under surface. 

 The test is more uniformly thin, and has stronger and 

 more sharply-pointed tubercles. The apertures are 

 also less distant. The tubercles are frequently com- 

 pound, bearing several aculeations. This is probably 

 the " Ascidia mamillaris, Delle Chiaje," of Thompson's 

 ' Natural History of Ireland,' but we think not of 

 Delle Chiaje, judging from his figure. 



17. Ascidia amoena .sy>. nor. 



(PI. XI, figs. 1 and 2 ; PL XVIII, fig. 2.) 



Bod n oval, semitransparent, greenish, largely at- 

 tached by the right side ; the upper slightly gibbous. 

 Branchial aperture a little way down the side, tubular; 

 anal about two thirds down, not very prominent. 

 7V*f transparent, nearly colourless, thickly covered 

 with stout, conical tubercles, generally with one, some- 

 times with two, small papilla? at the apex. Tentacles 



