248 THE VOYAGE OF H.M.S. CHALLENGER. 



The surface is smooth, but irregular, especially on the posterior part. The colour is 

 greyish, with a slight brown tinge. 



Length of the body of a single individual, 3 cm. ; breadth of the same, 07 cm. ; 

 height of the colony, 4 cm. 



The Test is cartilaginous and opaque ; it is moderately thin on the anterior half ; 

 posteriorly it is thicker, wrinkled, and incrusted with sand. 



The Mantle is well developed. 



The Branchial Sac is simple, but rather strong. The transverse vessels are all of one 

 size, with wide horizontal membranes hanging from them. No internal longitudinal bars 

 are present. The stigmata are regular, short, and narrow, with rounded ends. The fine 

 interstigmatic vessels are stout. 



The Dorsal Lamina is represented by a series of very large triangular languets, placed 

 closely. 



The Tentacles axe stout, and of two sizes, placed long and short alternately; there 

 are about twelve of each size. 



This is an irregular species, and the only specimen in the collection is almost certainly 

 to some extent abnormal (PI. XXXV. fig. 3). The united posterior ends of the ascidio- 

 zooids form a common irregularly-shaped base, which has probably been hypertrophied 

 by, and owes its irregularity to, adhering to the surface of a mass of Balani. 



The test is cartilaginous and strong. It is thick posteriorly and on the base, but is 

 much thinner at the anterior extremities of the individuals, and on their thoracic or 

 branchial regions. Two of the individuals are united together along one side by their 

 tests, which thus form a common investing mass. This is of course an abnormality, 

 probably caused merely by the very close proximity of the two individuals. 



The branchial sac is strong, the stigmata being slight and the transverse and inter- 

 stigmatic vessels stout ; the latter are usually twice as broad as the stigmata (PI. 

 XXXV. fig. 4). The horizontal membranes hanging from the transverse vessels are very 

 wide, and when laid out flat reach three-quarters of the way to the next transverse vessel, 

 covering the greater part of the row of stigmata between (PL XXXV. fig. 4). The stig- 

 mata are very regular. 



The languets in this species are very different from those seen in Clavelina oblonga 

 (compare figs. 5 and 8 on PI. XXXV.). Here they are numerous, placed close together, 

 thin and membranous, triangular in shape, and of large size. They spring from a broad 

 dorsal membranous band, and their bases are continuous with the broad horizontal 

 membranes extending round the branchial sac. 



One colony of this curious Clavelina, consisting of four adult individuals and several 

 buds, was obtained at Simon's Bay, Cape of Good Hope, in 10 to 20 fathoms. 



