TUNICATA. 339 



brittle. In macroscopic structure this species is sponge-like, there being numerous 

 passages and spaces bounded and crossed by bars of tissue (Plate VIII. , fig. 15). The 

 walls of the deeper passages are raised up to form numerous tubercles, as shown in 

 Plate VIII., fig. 16, which represents an optical section. 



There are very few cloacal openings visible on the colony, and the ascidiozooids, 

 which show as greyer and more translucent spots on the opaque white surface, seem 

 quite irregularly scattered over the surface (fig. 17). They are small and numerous 

 and have no marked characteristics. The stellate spicules are very abundant, 

 especially near the surface, and as a result the colony has a gleaming white 

 appearance. The rays of the spicules are short and blunt or even rounded at the 

 end (fig. 18). 



Leptoclinum ceylonicum, var. planum Plate IX., fig. 4. 



I place in this variety two large colonies, measuring 18 centims. x 11 centime, and 

 12 centims. x 12 centims., and one smaller (12 centims. x 7 centims.), which (along 

 with a colony of Gynandrocarpa imthurni) is figured from a photograph (fig. 4) 

 about half natural size. All three occur encrusting dead corals and masses of 

 Vermetus tubes from Station LXIX., Chilaw Paar, depth 8 to 11 fathoms, in the 

 Gulf of Manaar. They are very similar to the colonies of L. ceylonicum in structure 

 and as seen in thin sections, but differ in forming more of a flat continuous sheet 

 in place of lobes and bars. That difference, however, may be due to the firmer 

 sub-stratum which they encrust. They have not quite the same gleaming white 

 appearance, but this is a character in which parts of the same colony may differ ; so I 

 cannot consider these colonies from Station LXIX. as being of more than varietal rank. 



Leptoclinum ramosum, n. sp. Plate VIII., figs. 12 to 14, and Plate IX., fig. 3. 



This species is represented by a single very large colony growing over the dead 

 sclerobase of an Alcyonarian coral dredged just outside the pearl banks in the Gulf of 

 Manaar. The colony measures about 20 centims. in length and is about 7 centims. 

 across at the widest, an average width is 5 centims. The colony branches and 

 anastomoses in a characteristic manner (Plate IX., fig. 3) so as to leave numerous 

 spaces and passages. The branches or bars are about 5 millims. in diameter on the 

 average. The colour is a dead milk-white. Very few cloacal openings are visible, 

 and the ascidiozooids are not conspicuous. In most parts they are few and distant, 

 in some few places they are more abundant and more conspicuous. The marks caused 

 by the ascidiozooids vary in size from 0'5 millim. to 1 millim. across. 



The spicules are much larger than those of the last species and are more densely 

 packed on the surface, where they form an opaque layer even in thin sections 

 (fig. 12), and less densely deeper down, where they frequently run in lines so as to 

 form a reticulation (fig. 13). The rays of the spicules are much more regular 

 (fig. 14) and more sharply pointed than in the case of the last species. 



2x2 



