370 PROCEEDINGS OF THE NATIONAL MUSEUM. vol.52. 



ured along side. Hepatic coeca short, with few thick, saccular, 

 lateral pockets. Intestinal coecum small, saccular. Interbrachial 

 septum membranous. Superambulacral plates present. Tube-feet 

 pointed; ampullae large, double. 



The large saccular stomach consists of only a single chamber, there 

 being no trace of a dorsal division. The short hepatic coeca are 

 arranged about equidistantly on the circumference. In the stomach 

 is a bivalve — a Yoldia or related form — 22 by 12 mm. It is remark- 

 able that such a large body could be swallowed. 



Young. — ^Among the paxUlae of the abactinal surface are 28 young 

 starfishes, and in addition the forms where three others have been. 

 These vary in size from 3 to 8 mm, in diameter, and their distribution 

 coincides exactly with that of the gonads. Another curious circum- 

 stance: The largest young are found nearest the interradial hne, 

 while the others with a few exceptions are graduated in size distad, 

 just as the tufts of the gonads are. The smallest young are nearly 

 covered by the overarching paxillae, but as they increase in size the 

 paxillae are pushed aside and the intervening abactinal membrane 

 is stretched to extreme thinness. Viewed from the coelomic side, 

 the young, which form a sort of excrescence impinging upon the coel- 

 omic space, can be seen through the semitransparent integiunent. 

 The yoimg have no organic connection with the parent. Since they 

 lie immediately over the apertures of the gonads, it is possible that 

 they grow by feeding upon ova which are extruded for that purpose. 

 Or, there is a possibility that they may use coelomic fluid received 

 through a papular pore, produced by the simple process of digesting 

 the papula itself. The abactinal membrane is thin enough so that 

 fluid might be actually drawn through it if the stomach could per- 

 form a sucking process. Lastly, the tips of the rays are usually 

 turned upward a bit so that food currents might readily conduct 

 microscopic organisms to the mouth along the ambulacral groove. 

 An examination of the stomach of one of the larger individuals did 

 not reveal the exact nature of the food. The stomach was full of a 

 material, apparently sohdified by alcohol, in which I was able to dis- 

 tinguish what appeared to be fragments of cells, but no siUcious or 

 calcareous remains. 



The stomach of a small individual was partly everted. The cotype, 

 a male, has no young on the abactinal surface. 



Sladen, in the Asteroidea of the Challenger expedition,^ has figured 

 a specimen of Leptychaster Jcerguelenensis Smith, with numerous 

 yoimg on the abactinal surface. In this species the young leave the 

 arcade-hke spaces among the paxillae, and remain on the surface of 

 the paxillae with their actinal side outward. 



Type.— €at. No. 37029, U.S.N.M. 



« Challenger Asteroidea, 1889, pi. 31, flg. 1. 



