A, H. CLARK : THE CRINOIDS OF THE INDIAN OCEAN. 201 



all until near the tip, and hence appearing somewhat stouter; they are composed 

 of about fourteen segments; distal pinnules moderately slender, 12 mm. long with 

 twenty segments, the first trapezoidal, ahnut twice as broad distally as its 

 median length, the second trapezoidal, somewhat broader distally than the 

 median length, the remainder slightly longer than broad ; the dorsal ridge is very 

 sharp and more or less spinous. 



The colour in spirits is white. 



Locality. — Malay Archipelago ; 30 faiJioms. — One specimen. 



Remarks. — The single known specimen of this species is, unfortunately, 

 badly broken, though it is possible to piece it together so that most of its charac- 

 ters maby be made out. 



There is a possibility that this is identical with Th. magnicirra described irom 

 South Africa by Professor Bell, but neither his diagnosis nor his figure is suffi- 

 ciently accurate to admit of satisfactory comparison. He states that in magni- 

 cirra the centrodorsal bears ' three or four vertical rows " of cirrus sockets, but 

 his figure shows five in one half of the centrodorsal only ; he says that the cirri 

 " may be as much as 70 mm. long," but his detailed figure of a cirrus, accord- 

 ing to the explanation of the plate, shows one 41 mm. long, while that on hi? 

 drawing of the entire animal is 60 mm. long. He says further that " no pinnules 

 are very long, but they are all stout," and figures them all as slender. There is 

 figured " an arm from the side, showing the form of the plates and pinnules, as 

 well as the remarkable subsidiary plates between the arm joints " ; this figure is 

 four times natural size and shows PP a-k, which are given as from 3 mm. to 4 mm. 

 long (corrected) : as his specimens are not much smaller, apparently, than the one 

 under consideration (cirri 70 mm., arms 100 mm.) this would make these pinnules 

 proportionately only about one half as long, and, judging from Mr. Berjeau's 

 figure, this appears to be the case. ; It should be noticed that the portion of 

 arm figured (X4) is shown as 75 mm. long, while the same portion of an arm 

 measured on the figure of the entire animal (X 2) is 47 mm. "The remark- 

 able subsidiary plates " were long ago described by P. H. Carpenter. The pin- 

 nules in magnicirra are figured as arising in pairs from alternate brachials, an im- 

 possible arrangement, and, moreover, have a certain suppleness far removed from 

 what is actually found in the Thalassometridfe. Professor Bell placed the species 

 •' Tie^t to A. angustiraclia^' (=Adelometra angustiradia ; Antedonidse) of Carpen- 

 ter's " Savignyi group" in spite of its very obvious relations to Carpenter's 

 " Granulifera group" (Thalassometridae). The delineation of the pinnules of 

 the inner side of the arm is misleading, as one naturally would consider them to 

 be the outer pinnules if there is nothing said to the contrary, antl would therefore 

 obtain a very erroneous idea of the animal. 



THALASSOMETRA SENTIFERA. 

 Crotalomelra sentifera 1909. A. H Clark, Proc. Biol. Soc. Washington, vol. 22, 

 p. 147. 



