PEOP. W. A. HEEDIIAN ON BRITISH TUNICATA. 430 



whicb he considers to belong to Alder and Hancock's species, and 

 of which he has given lately a full description. 



7. A. crassa, Hnk. — I have examined Canon Norman's type 

 specimens collected at Jersey in 1809. I think this is a good 

 species ; and to Hancock's description * I shall merely add a 

 few notes and some figures from the specimens (see PI. XXXIY. 

 figs. 7-10). 



The branchial and atrial apertures are perfectly sessile and 

 inconspicuous. The test is thick, solid, cartilaginous, and stiff ; 

 vessels are present. The mantle is strong and muscular on the 

 right side (PI. XXXIV. fig. 10) and along the dorsal edge. The 

 branchial sac is notable for the very stout papillae, which are of 

 two sizes, it is true ; but both kinds are so large that they nearly 

 touch at their bases, and practically all the space on the bar 

 between two main papillae is taken up by the intermediate one 

 (PI. XXXIV. fig. 9). 



The tentacles are numerous and irregular in size. They seem 

 more numerous and densely crowded at the dorsal and ventral 

 edges, and both smaller and fewer at the sides. 



The dorsal tubercle is large and of rounded outline ; the 

 aperture is anterior, and both horns are turned in, one being 

 long and curved (fig. 8). 



8. A. inornata, Hnk. — I have not seen any specimens of this 

 species. From the description it seems certainly, as Hancock 

 himself says, rather like Alder's A. pleheia ; and I do not see 

 that the characters of the branchial papillae and dorsal lamina 

 establish aoy real distinction between the two species. 



9. A. prodncta, Hnk. — I have examined Canon Norman's type 

 specimens dredged in the Minch in 1866. This species is certainly 

 closely allied to A. pleheia, and the smaller (younger) speci- 

 mens are very like that species ; but stil] I think A. producta 

 may be regarded as a distinct species. I have found specimens on 

 stones in East Loch Tarbert below extreme low tide which I 

 refer to this species. 



To Hancock's description I would merely add the following 

 remarks (see PI. XXXV. figs. 1-7) : — The test seems to me rather 

 soft and flexible (even in Canon Norman's spirit specimens) and 

 thin, especially on the under surface. The mantle is very thin and 

 is not very muscular, the muscles being, in fact, scarcely visible 



* Ann. & Mag. IVat. Hist. 1870, p. 359. 



