1910.] FROM MERGUI ARCUIPELAGO. Sl'A 



North Atlantic Ocean, and from the "Western Pacific (China and 

 Eastern Australia), it has not hitherto been found in the Indian 

 Ocean. 



Calycella oligista *, sp. n. (Plate LXXVI. figs. 3 & 4.) 



Trophosome. The colony is epizoic, and consists of a creeping, 

 delicate stolon which lies in close contact with the specimen upon 

 which it occurs. From this stolon liydrothecie spring at irregular 

 intervals. 



The hydrothecfe are exceedingly minute, delicate, liyaline, and 

 ti'ansparent, without a tr.ace of the smoky tint which charac- 

 terises C. syringa. In shape they are tubular and cylindrical, of 

 approximately the same diameter for the greater portion of their 

 length, although the proximal half is usually slightly bulged, and 

 tapeis, more or less rapidly, to join the stalk. The margin of the 

 hydrotheca, which is very slightly everted, is definite, and is of 

 considerable strength, for it is seldom that it is found in a 

 collapsed condition. It is divided into shallow crenulations, 

 similar to those in C. syringa, each of which sulitends the base of 

 an opercular valve. In no case was a dujiliration of the margin 

 noticed. The operculum is distinct from the liydrothecal wall, 

 and is composed of about twelve to fourteen exccedinglv delicate 

 valves, difficult to distinguish. The cavity of the hydrotheca is 

 separated from that of the stalk by a distinct but delicate 

 diaphragm. The stalk is usually very short, so that the hydro- 

 theca almost rests on the stolon, but in one case (PI. LXXVI. 

 fig. 3) a well developed stalk was observed. This stalk was marked 

 by a few irregular indentation.s, but in other cases the stallcs were 

 smooth, and ringing of a regular nature never occurred. 



The hydranth is large compared with tlie size of the hj'drotheca. 

 It is attached by a basal disk to tlie hydrotheca! wall immediately 

 above the diaphragm, and is continued upwards ns a cylindricnl 

 body with conical hypostome, surrounded by a whorl of about 

 seven to ten tentacles. The ectoderm is thick, and the tentacles, 

 in contraction, are dumpy and stout. 



The gonosome was not observed. 



Dimensions : — 



Stolon, diameter 30/*. 



Hydrotheca, depth 120-138 /a. 



,, greatest diameter 45-66 /i. 



Localities. St. 23, Five Islands, 8 to 12 fathoms, rock and .sand, 

 and mud ; very rare, on Idia pristis. St. 35, between Warden 

 Island, Howe Island, and Lyail Island, 15 to 20 fathoms, rock 

 and .sand ; very rare, on Idia pristis and Thyroscyphns vitiensis. 



Systematic position. — This species differs remarkably in size, 

 coloiar, texture, and in the develojiment of the peduncle and its 

 ringing from C. syringa, although there is a similarity between 



• AAVyiffros, smallest. 



Proc. ZooL. See— 1910, No. LIII. 53 



[15] 



