100 BRITISH TUXK'ATA. 



the stomach. The oviduct passes through the loop of 

 the intestine, and its rounded extremity is seen on re- 

 moving the lining-membrane ; here it becomes united 

 to the main branches of the ovary. The male caeca, 

 which are minute, numerous, and branched, appear at 

 the surface of the right side of the intestine ; a few 



are also observed on removing the lining membrane 



~ 



on the left side. 



This interesting species is closely related to A. pi an a 

 as is proved by the transverse position of the intestinal 

 loop, which is arranged exactly as it is in that species ; 

 and moreover the visceral mass is attached to the right 

 side of the test by a membranous band which passes 

 through the loop of the intestine in the same manner 

 as it does in A. plan a. ; the band being adherent to the 

 lining-membrane at the left side of the intestine. It is 

 nevertheless readily distinguished from that species by 

 the arrangement of the tentacular filaments; bv the 



ft/ 



form of the branchial papillae ; by the colour and pecu- 

 liar character of the blood-channels of the test; and by 

 several other minor features. 



10. Ascidia rudis Alder. 

 (PI. VII, figs. 1-4; PL XVII, fig. 8.) 



Axcidia rnilis ALDER in Ami. Nat. Hist. (3) XI (1863), p. 155 

 [; NORMAN in Eep. Brit. Assoc. 1867 (1868), p. 439, and 

 op. cit. 1868 (1869), p. 302]. 



Bod [i oblong or ovate, rather irregular, depressed, 

 greenish, attached largely by the side. Apertures dis- 

 tinct, the branchial terminal, the anal generally about 

 half way down; ocelli red, uniform. Text thick, coria- 

 ceous, coarse, wrinkled, and very slightly tubereulated, 

 sometimes nearly smooth. Mantle bluish-green, with a 

 yellowish tinge towards the upper part, the apertures 

 distinctly tubercular, the anal tube often much 

 extended, and entering into a kind of sheath in the 

 substance of the test. Tentacular "filaments few and 



