88 BRITISH TUNIC ATA. 



branchial ; the oral lamina likewise differs in some 

 particulars, as do also the reproductive organs. 



AVe have seen only one individual of this species, 

 and, as the description \vas drawn up some time after it 

 had been in spirit, it is probable that its colour may 

 have been much brighter than is represented, and 

 indeed may have been somewhat different in kind as 

 well as in degree. It would seem, too, that the blood 

 was probably red ; for the blood-channels were in 

 many parts clogged with a reddish matter. 



6. Ascidia crassa Hancock. 



(PI. XVII, fig. 4; PL XIX, fig. 3 ; PI. XX, fig. 5; and 



fig. 17 in text.) 



[A*et(li(i cratxa HANCOCK in Ann. Nat. Hist. (4) VI (1870), 

 p. 359.] 



Bfnli/ broadly oval, a little depressed, deeply and 

 irregularly wrinkled, of a pale flesh-colour, adhering 

 by various parts to seaweeds. Apertures distant, ses- 

 sile ; branchial sub-terminal ; anal about half-way 

 down the side. Text very thick, hard, cartilaginous, 

 pellucid, irregularly and strongly wrinkled, of a pale 

 flesh-colour. " Mantle rose-coloured, deeper towards 

 the margins and over the alimentary canal ; the tubes 

 of the apertures short, particularly the branchial one, 

 which is sub-terminal; the anal is a little produced 

 and doubled over towards the left side. Tentacular 

 filaments numerous, well-developed, unequal in size. 

 Braiirliial sac minutely plicated, with obtuse papillae 

 alternately large and small, the stomata very small 

 and elliptical. Oral lamina delicately ribbed trans- 

 versely, and minutely pectinated ; by the side of the 

 mouth the pectinations are increased in size and re- 

 place the lamina. 



Li'iiijtli two inches and a quarter; breadth an inch 



and a half. 



. Between tide-marks, attached to seaweeds. 



