12 BEITISH TUNICATA. 







pool, and Helforcl River, Falmouth, Cornwall (Cocks, 

 1849).] 



WALES. [Anglesey (Pennant, 1812).] 



SCOTLAND. [Aberdeen (Macgillivray, 1843). North 

 Uist, Outer Hebrides (Mclntosh, 1866). "In Zetland 

 seas " (Fleming, 1828). Orkney and Shetland (Forbes 

 $ Goodsir, 1839). West Voe, Whalsey Skerries, 

 Shetland, at low water (Norman, 1868).] 



IRELAND. [Strangford Lough, Down (Thompson, 

 1840).] 



First record. Fleming, 1828. [(?) Ellis & Solander, 

 1786. Pennant, 1812, as Ascidia virescens ; coll. 1 800.] 



Ciona intestinalis is remarkable for the softness and 

 great contractility of its test (PL XXI, figs. 1-3) ; 

 when contracted the upper part is capable of being 

 withdrawn within the lower part like the finger of a 

 glove, and the latter is much shortened and thrown 

 into transverse wrinkles. Usually it is extensively 

 attached by the side, the anterior extremity being 

 more or less free, so as to admit of its invagination. 

 The vascularity of the test is confined to the lower 

 part ; the branches are not numerous and terminate in 

 slightly enlarged, elliptical extremities. 



The mantle (fig. 28) is remarkable for the strength 

 of the longitudinal muscular bands which pass into 

 the tubes and reach to the bottom of the pallia! sac, 

 where the component fibres are separated a little ; the 

 transverse fibres are very delicate and seem to be 

 chiefly confined to the left side. 



The branchial sac (PI. XXI, fig. 5), like the body, 

 is considerably elongated; it does not reach to the 

 bottom of the mantle, though it overlies a little the 



O 



left side of the first intestinal loop. 



The stomach is a well-defined, ovate sac, lying trans- 

 versely in the visceral chamber, the wide or cesophageal 

 extremity towards the ventral margin. The oesophagus 

 is a broad tube of some length ; it turns immediately 

 upwards from the stomach and opens into the bottom 

 of the branchial sac at the ventral margin; the intestine 



