196 CEYLON PEARL OYSTER REPORT. 



There is one large Polian vesicle, 4 millims. lons>', and a single stone canal. 



The gonads are present only on the right side of the dorsal mesentery. 



Although the tentacles are not present, I have decided to place this specimen in 

 the genus Actinocucumis, hecause of the arrangement of the pedicels, and also 

 because of the presence of papillae. 



Colochirus quadrangularis, Lesson. 



Colochirus cceruleus, Semper (2), 1868. See also Thef.l (7). 



Four specimens from South of Adam's Bridge (Stn. LIV.). 



Lengths, 75 millims., 60 millims., 30 millims., and 40 millims. 



These specimens agree well with Theel's description. 



Colour in spirit : Yellow and dark brown, with a very faint tinge of violet. 



Distribution : Philippines, E. Africa, Australia, E. Indies, Ceylon. 



Colochirus quadrangularis, var. mollis, nov. Plate IT., fig. 21. 



One specimen from South of Thanni-Kodi, Adam's Bridge (Stn. LIV.), 8 J fathoms. 



Length 100 millims. 



This differs from Colochirus quadrangularis in the texture of the body wall. 

 Instead of being very hard, thick, and rough, as in Col. quadrangularis, the skin is 

 soft, thin, and comparatively smooth. 



Although this specimen is larger than any of those of Col. quadrangularis in 

 the collection, yet the papillae at the four angles of the body are much smaller 

 comparatively. 



The colour of the animal also differs from that of the Ceylon specimens of Col- 

 quadrangularis. The following is the account of the colour of the living animal, as 

 noted by Professor Herdman : 



"Colour of body a uniform orange, slightly mottled with a paler tint. The crown 

 of tentacles are mottled yellow on a dark brown ground. The region between the 

 five valves at the base of the tentacles is white." Plate II., fig. 21, is from a drawing 

 in Professor Herdman's notes showing the living animal with tentacles expanded. 



I think it advisable to call this specimen a new variety of Col. quadrangularis, 

 with which it agrees in other characters. 



Colochirus doliolum (Pallas). 



Actinia doliolum, Pallas, 1766. Colochirus australis, Lumvio (9), 1875. Also Theel (7). 



Two specimens from South of Adam's Bridge (Stn. LIV.). 

 Lengths, 20 millims. and 8 millims. 



The larger of these specimens agrees very closely with the descriptions of this 

 species, both in the form of the body and also in the nature of the deposits. 



