TUNICATA. 335 



large circular depressions, about 1*5 millims. across, vvliich probably correspond to the 

 ends of the ascidiozooids, but no distinguishable remains of the latter are visible on 

 dissection. It is probable that the colony was either dead or regenerating at the 

 time when it was collected. 



Amaroucium sp. ? Plate VIII., fig. 4:3. 



There are several small colonies from the Gulf of Manaar which probably belong to 

 this or one of the allied Polyclinid genera. The largest colony is shown in fig. 43. 

 They are mostly in poor condition, or have lost the ascidiozooids, and consequently I 

 only refer to them for the purpose of stating that a species belonging to this group 

 occurs in the locality. 



Psammaplidium ceylonicum, n. sp. Plate VIII., figs. 8 to 11, and Plate IX., fig. 9. 



Colony a large and very sandy mass of rather flabellate form, with vertical walls 

 and buttresses, recalling the appearance of some sponges (see Plate IX., fig. 9); 

 surface lobed, uneven and rough, divided up into small areas (Plate VIII., fig. 11) 

 and very thickly encrusted with sand; size, 15 centims. x 10 centims. x 8 centims. 



Ascidiozooids small for the size of the colony, scarcely 3 millims. in length, and less 

 than 1 millim. in greatest breadth ; abdomen and post-abdomen very slender, thorax 

 wide (Plate VIII.! , fig. 8). 



Test densely crowded with sand-grains, having the ascidiozooids arranged in its 

 superficial layer only (fig. 10). 



Mantle with both longitudinal and transverse muscle bands on the thorax ; over 

 the abdomen the longitudinal bands coalesce into two strong bundles which course 

 along the post-abdomen and terminate in two projecting points (fig. 8), which show 

 strong ech inations under a high power (fig. 9). 



Alimentary Canal long and slender (fig. 8) ; stomach folded longitudinally. 



Tailed larvae are present in the colony (taken March 7). 



Locality : Station LIV., in north part of Gulf of Manaar, 10 to 30 fathoms. 



There are several smaller colonies, and fragments, from various parts of the Gulf of 

 Manaar which are indistinguishable in structure from this species, although they may 

 differ somewhat in appearance on account of the colour or size or amount of the sand- 

 grains taken up by the test. 



Psammaplidium aurantiacum, n. sp. Plate VIII. , figs. 2 to 6, and Plate IX., fig. 8. 



Colony a large rounded mass (Plate IX., fig. 8), slightly lobed, with a smooth 

 surface only slightly sandy ; of a dull orange colour ; size, 9 centims. x 7 centims. 

 x 4 centims. 



Ascidiozooids up to 3 millims. in length, and rather less than 1 millim. in greatest 

 breadth ; dull yellow in colour, embedded in a clear orange-grey test. The anterior 

 ends of the ascidiozooids as seen on the surface are grey. 



