108 CATALOGUE OP THE MOLLUSCA 



attached through its whole length by a rather inconspicuous disc. 

 Branchial aperture not quite terminal, at the anterior end, pa- 

 pillose, very little elevated, and divided into eight tubercular seg- 

 ments. Anal aperture situated a little below the branchial one 

 on the left side, not prominent, with six tubercles. Outer tunic 

 tough, sub-opake, nearly smooth but rather coarse ; inner tunic 

 opake white or flesh-coloured with a few spots of red between 

 the apertures. The red ocelli of the apertures, which are scarce- 

 ly visible outside, are distinct in the inner tunic. Branchial 

 sac reticulated, with slender papillae at the intersections of the 

 larger meshes. Length three-quarters of an inch ; breadth 

 about one-third less. 



Attached to the underside of stones, within tide-marks. Culler- 

 coats, not common. — A. H. 



Professor E. Forbes has referred our drawings of this species 

 to Ascidia jyrunum of Miiller, but in this opinion we cannot 

 agree. A. primum is described as rounded, lax, hyaline, and very 

 pellucid, and is a free or slightly attached species dwelling in mud. 

 It consequently does not belong to this division of the genus. 

 8. A. PELLUciDA, Aid. and Hanc. 



Body depressed, hyaline, subtriangular, attached laterally by a 

 broad disc. Branchial aperture terminal, wide and tubular, divided 

 into eight segments with red ocelli. Anal aperture situated a 

 little below it on the left side, tubular and curved inwards 

 towards the upper surface, with six ocellated segments. Outer 

 tunic smooth, coriaceous, colourless and perfectly transparent. 

 Inner tunic not above one-half the size of the outer one, opake 

 yellowish white, inclined to red on the lower part. Length half 

 an inch. 



Under stones within tide-marks, Cullercoats, rare, — A. H. 



Order. — (Les Ascidies sooiales, Milne Edwards.) 

 Family. CLAVELLiNiciE, Forbes. 

 126. CLAVELLINA, Smigny. 

 1. 0. LEPADIFORMIS, Milll. 



ClavelUna lepadiformis, Forb. and Hani. Brit. Moll. i. 26, t. 

 E, f 1. 



