Boone, Echinodermata, Cruises of "Ara" and *'Alva" 189 



nitely a factor in this complex spicule formation are occasional 

 slender, spiral spicules, consisting of one and a half to two or 

 more coils, with the distal ends each furnished with a cluster of 

 five or six slender, acuminate spines, all of which diverge obliquely 

 outward. There are also small irregular bodies, somewhat clavate 

 with nodes on the enlarged ends, these node articles sometimes 

 have three branches instead of two ends. There are also small 

 disks irregularly circular or oblong, sometimes with the margin 

 sinuate-convex, sometimes tri-lobed, each with the surface pierced 

 with two or three small holes. 



The smaller specimen is figured in plate 69. The plate of 

 spicules (plate 70) is based upon micro-dissections from the 

 dorsal and ventral tissues adjacent to the ambulacra, about mid- 

 way their length, from both specimens. Every kind of spicule 

 depicted was found repeatedly in each specimen. 



Colour : Not recorded from the living specimens. 



Peyitacta arae has the general appearance of the old and rather 

 widely distributed Indo- Pacific species, P. tuber culosus (Quoy and 

 Gaimard),^ but is unquestionably distinguished therefrom by the 

 presence of entirely different kinds of calcareous bodies in the 

 perisome. 



Order: PARACTINOPODA 

 Family: SYNAPTIDAE 

 Subfamily: Synaptinae 



Genus: EUAPTA Ostergren 

 Euapta godeffroyi (Semper) 



Type : Semper's type material came from the Samoan Islands, 

 where it was collected by Dr. Graffe. It is deposited in the Museum 

 Godeffroy. 



Distribution : This species is known from the littoral zone 

 of the Indo-Pacific, where it has been recorded from the following 

 localities: Mauritius (Haacke, Ludwig) ; Thursday Island, Torres 

 Strait (Sluiter) and Mer (H. L. Clark) ; Great Sangir Island, 



^Holotlturia tuberculosa, Quoy and Gaimard, 1833, Voyage de L' Astrolabe. Zoologie, T. IV, 

 p. 131. 



