26 clavelinidyE. 



these two genera into a separate and most natural group, 

 under the name of "Ascidies sociales." 



CLAVELINA, Savigny. 



Individuals and groups connected by creeping, radiciform 

 prolongations; the Ascidians arising from them having 

 elongated, erect, more or less pedunculated bodies. Bran- 

 chial and anal orifices without rays. Outer tunic smooth 

 and transparent. Thorax usually marked with coloured 

 lines. 



C. LEPADIFORMIS, 0. F, Mullcr, (Sp.) 



Ascidia lepadiformis, 0. F. M'dller, Zool. Dan. t. 70, f. 5. — Clavelina lepadi- 

 formis, Savigny, Mem. pt. 2, p. 174 ; Fleming, Brit. An. p. 468 ; Milne- 

 Edwards, (Mem. Asc. Comp.,) Mem. Inst. vol. xviii. p. 266, pi. 1, fig. 1 , and pi. 2, 

 fig. 1, l'>. 



Plate E, fig. 1. 



Thorax forming a third part of the length of the adult indivi- 

 dual, and marked with yellow lines ; stomach of a bright orange, 

 placed near the middle of the abdominal portion of the animal; 

 part of the intestine of the same colour. 



Usual length from one-half to three-fourths of an inch. Abun- 

 dant on rocks and stones at low-water in many places, especially 

 on the west coast of Scotland. Strangford Lough, Mr. W. 

 Thompson. Connemara. " Very generally diffused ; I have met 

 with it on the Devonshire, Cornish, and Northumberland coasts, 

 and in Lamlash, Rothesay, and Oban bays in Scotland," Mr. Alder. 



The mode of germination of this species has been well described 

 by Milne-Edwards. " If we examine with care the foot of a Cla- 

 velina lepadiformis, we see that the animal adheres to the soil 

 by more or less numerous radiciform prolongations of the tegu- 

 mentary tunic ; and usually we find also cylindrical filaments, 

 which, mingled with these roots, and formed externally by the 

 same tissue, creep also on the surface of the soil, but are hollow, 

 and internally furnished with a membranous tube. This tube is 

 continuous with the internal tunic of the Ascidian ; and the circu- 

 lation which is seen in the interior of the abdomen of the latter is 

 equally continued into the appendicular canal. This stalk-like 



