288 
THE VOYAGE OF H.M.S. CHALLENGER. 
The Test is not very hard ; it is flexible, but tears easily. It is of a dirty white colour, 
and is opaque. The matrix contains the usual small test cells, and also large numbers of 
stellate calcareous spicules, which are most closely placed in the regions between the 
anterior ends of the Ascidiozooids. In the deeper parts of the test they are not so 
abundant as in the superficial layer. 
The Mantle is moderately strong and muscular. 
The Branchial Sac is large and well developed. The stigmata are long, and are 
arranged with regularity. 
The Endostyle is conspicuous. 
The Dorsal Lamina is represented by a series of long languets. 
Loccdities . — (a) Off San lago. Cape Verde Islands; .depth, 100 to 125 fathoms 
(one colony). (6) Off San lago. Cape Verde Islands; depth, 10 to 20 fathoms (one 
colony), (c) Simon’s Bay, Cape of Good Hope; depth, 10 to 20 fathoms (several 
colonies). 
There are a number of specimens of Leptoclinum in the Challenger and “Porcupine” 
collections which are either very closely allied to or identical with Verrill’s Leptoclinum 
alhidum. In 1871 ^ Professor Verrill described briefly, without figures, the species 
Leptoclinum alhidum and its variety lutecium? I have been enabled to examine several 
specimens of both these forms from the collections sent out to museums by the United 
States Commission of Fish and Fisheries, and the new specific description which I have 
considered it necessary to give above is derived partly from these American specimens 
and partly from those in the Challenger collection. 
A specimen obtained during the Challenger Expedition, off San lago. Cape Verde 
Islands, from a depth of 100 to 125 fathoms, agrees closely with preserved specimens both 
of Leptoclinum alhidum and of Leptoclinum alhidum, var. lutecium. It measures about 
3 '5 cm. in length and 2 cm. in breadth, and is very thin, scarcely 1 mm. in the thickest 
part, and in many places much less. It occurs incrusting a lump of Sponge, over which it 
has spread irregularly. There is also a very small colony of probably the same species 
attached to the Sponge. 
The Ascidiozooids are moderately large and rather conspicuous. They are placed 
slightly further apart than is usual in Leptoclinum alhidum. They are of a greyer 
colour than the surrounding test. No common cloacal apertures are visible. 
The test is opaque between the Ascidiozooids, and translucent over them, where 
there are fewer spicules present. The clearer areas thus formed on the surface of 
the colony are generally elliptical in shape and are about 0’4 mm. in the longer 
diameter. 
1 Amer. Journ. Sci. and Arts, ser. 3, vol. i. No. 6, p. 443. 
2 Named as a distinct species in the paper quoted. 
