158 Proceedings of the Royal Physical Society. 



Malcolm Island, 13 to 18 fathoms, coarse sand and broken shells (three 

 examples). St. XVIII., West and south-west of Paway Island, 10 to 21 

 fathoms, sand, shells and rock (six examples). St. XXV., Gregory Group and 

 Crichton Island, 4 to 14 fathoms, stones and broken shells and rock 

 (41 examples). 



P. gorgonia is a littoral form, and is very widely distributed up to a 

 depth of over 40 fathoms. It has been taken from the coasts of Natal, 

 Mozambique, Zanzibar, Madagascar, Ceylon, Andaman Islands, Fiji Islands, 

 Samoa, Thursday Islands, etc. 



(2) Ophioglypha sinensis Lyman, 1871. 



This species is represented by eleven specimens from five stations. In all 

 my examples there is found only one pit or depression between the ventral 

 margins of the lateral arm-plates, and this occurs at the very base of the arm, 

 ^.e.,on the proximal side of the first ventral arm-plate. In this respect Lyman's 

 figure, plate i., fig. 1 (1871), is misleading in that he indicates depressions 

 even beyond the disc, a possible error to which Koehler (1898) draws 

 attention, stating that, of seven specimens examined by him, only two showed 

 a couple of depressions, while the others have only one. Koehler suggests 

 that the smaller size of his examples may account for the difference between 

 his and Lyman's examples, those of the former being considerably smaller. 

 This explanation, however, can scarcely be admitted, for my specimens, the 

 largest of which has a disc-diameter of over 8 mm., are very similar in size to 

 the one selected by Lyman as characteristic of his examples. It may be 

 added that the single depression is very distinct, and reminds one of the 

 ventral pits in Ophiura ciliaris (Linn.). 



The innermost ventral arm-plate, immediately outside the depression to 

 which reference has been made, is somewhat triangular in shape. From the 

 figure which Lyman gives, it appears as if the margins of the ventral arm- 

 plates are gently rounded, except on the proximal side, and the distal edge 

 arc-shaped, whereas, in my examples, these plates have the lateral edges 

 straight, the distal edge almost straight, and the proximal edge also straight 

 except for a slight projection at the line of junction of the lateral arm-plates 

 along the middle of the ventral surface of the arm. The ventral arm-plates 

 are thus almost rectangular. They are twice as broad as they are long, and 

 they are small and widely separated. So widely separated and so nearly 

 linear are these transverse plates, that in spite of their presence the sutures 

 formed by the junction of the ventral margins of the lateral arm-plates give 

 one the impression of forming almost a continuous straight line along the 

 centre of the arm. 



