166 Proceedings of the Royal Physical Society. 



Locality. — St. IV., North-west of King's Island, 8 to 25 fathoms, rock and 

 sand, dredge (one example). 



Some examples of this species, which is apparently not widely distributed, 

 were found by the " Investigator,'' near the coast of Orissa, at a depth 

 of 11 fathoms, and also 30 miles south of Coconda, at a depth of 4 to 

 5 fathoms. 



(13) Ophiocnemis marmorata (Lamarck). 



Duncan's remarks (1889, pp. 103, 104) on Lyman's (1882) amended 

 definition of this species of Ophiocnemis, which Midler and Troschel 

 insufficiently diagnosed, are very full. The four examples of this species 

 in my collection are from one station, and have a disc-diameter of 10, 

 15, 15, and 16 mm. respectively. Duncan's specimen, also from the Mergui 

 Archipelago, had a disc-diameter of 13 mm. and an arm-length of 70 

 mm. 



While my specimens conform to Duncan's description, I note the 

 following points : — The disc is notched at the insertion of the arms. Four 

 rows of very short nodular stumps extend inwards interradially from the 

 margin of the disc, and two rows of similar stumps extend inwards radially, 

 separating the large radial shields from each other. These rows all meet 

 near the centre of the disc. Thus the whole dorsal disc-surface is covered by 

 the ten large radial shields and by these short stumps. The slate-coloured 

 radial shields have numerous irregular dark spots, and are smooth except 

 that the nodular stumps stretch round the edge of the disc, even invading 

 the outer margin of the radial shields. The interbrachial ventral surface 

 is naked, except for a few short scattered stumps towards the outer margin. 

 There is an obvious genital process on the outer side of the mouth-shield. 

 Lyman's figure does not show that the mouth-shield is much broader than 

 long, and that the side mouth-shields are pointed. The innermost ventral 

 arm-plate lias a conical projection directed towards the centre of the mouth. 

 Close to the disc, on the first and second arm-joints, there are at least six 

 spines, but beyond this there are only four or five. The second and third 

 are much longer than the uppermost, and the lowest one is very small 

 and pointed. 



Locality. — St. XXX., Fly Island, Observation Island and S.W. of Domel 

 Island, 8 to 15 fathoms, rock and sand (four sjjecimens). 



This species has also been taken from Zanzibar, Ceylon, Madras, 

 Singapore, Sonda Islands, N.W. Australia, etc., up to a depth of 34 

 fathoms. 



