110 BRITISH TUNICATA. 



and less strongly on the left ; the margin is strongly 

 pectinated, with one or more points on the membrane 

 between those of the ribs which are large and stouter 

 than the rest. The margin on the left side is bordered 

 with a rather wide band of large, curved, pointed, 

 papillae ; they are mostly irregularly disposed, but the 

 largest, which are the lowest down, are arranged with 

 considerable order in a doable row. Near the month 

 they are much crowded. The belt of tentacular points 

 on the left side of the mouth is advanced for some 

 little distance in a straight line upwards ; in all there 

 are about twenty rather large points. Below the mouth 

 the oral lamina gradually dies out and is succeeded by 

 a few minute diagonal plaits or folds. The branchial 

 tubercle is looped-formed, with the left extremity 

 turned outwards. The collar of tentacular filaments 

 is placed very little in advance of the branchial margin ; 

 they are numerous, closely-set, rather stout and long, 

 with their bases adherent to the mantle for some dis- 

 tance upwards ; a few smaller ones are interspersed, 

 which, bending forward in front of the others, give 

 somewhat the appearance of an anterior or second 

 row. 



The ovary is confined to the left side of the alimen- 

 tary tube ; it is composed of ramified tubes which are 

 spread over the inner margin of the intestinal loop, 

 forming there a small patch of involved branches. 

 The male casca are wide and obtuse, frequently irregu- 

 larly lobed, but usually bifid ; they coat the greater 

 portion of the right side of the alimentary tube, but 

 do not extend to the posterior extremity of the stomach. 

 The cells spread over the visceral mass are large, with 

 a dark conspicuous nucleus in each. 



A. inornata is allied to A. ^lel>eia, but differs from it 

 in many respects, and may at once be distinguished by 

 the narrowness of the mantle and branchial sac, and 

 likewise by the characters of the branchial papillae and 

 oral lamina. 



