ASCIDIA SCABRA. 131 



of the pallial sac to nearly half way up ; the rectal 

 portion diverges to the base of the excurrent tube, 

 where it terminates in a wide anal orifice, with a 

 smooth reflected margin. The left side of the stomach 

 is thickly covered with vesicular matter which is 



i/ 



extended over the intestinal loop, and this, as well as 

 the stomach and oesophagus, is yellowish, blotched, 

 and marked with red ; the rectum is hyaline. 



We have followed the opinion of Professor Sars in 

 considering the AsciJni. ttsprrx<t of Miiller to be the 

 young of this species, which is extremely variable 

 both in form and colour. Specimens with the mantle 

 blotched with red are much more common than those 

 which have it all of that colour. 



Axcidia x<:/ti- in some of its forms bears a great 

 resemblance to A. sordida, whose place it seems to 

 take 011 the south-west of Great Britain, though 

 generally found in shallower water, and sometimes 

 between tide-marks. It is smaller, more largely 

 attached, and more tuberculated than A. sor<UJ</, and 

 has the orifices situated rather more to one side ; 

 and moreover, while the latter belongs to the division 

 with the branchial sac papillose, A. scaltra has it iion- 

 papillose. Its closest allies, however, are [JL Morei,~] 

 A. <y /#/*, and A. Nonunni; but from each of these it 

 has many distinguishing features. 



[Var. albida Nobis.] (PI. XV, figs. 3 and 4.) 



[Avidia albida ALDER and HANCOCK in Trans. Tyneside 

 X. F. Club, I (1848), p. 200.] 



A colourless variety not infrequently occurs, entirely 

 devoid of blotches and spots, except those of opaque 

 white. This pretty variety might easily be taken to 

 be a distinct species ; but it agrees in all essential 

 characters with A. scalni. 



ENGLAND. Cullercoats, Northumberland (Alder 

 Htntcock). [Falmouth, Cornwall (Cocks, 1849).] 



