Anatomy of the Teninopleuridte. 127 



the psellion, and nearly reaching tlie circumference of the 

 free end of the cup, is very decidedly divided into four parts, 

 and each part is composed of a reticulation which has five or 

 six spoke-like processes which traverse the lamina of the 

 circlet and are free at its circumference, some ends being 

 simple points, others double or cellular. Between the spokes 

 are cross pieces, and hence the reticulate and fenestrated 

 appearance. At the sides of each lamina^ that is at the 

 four divisions of the circlet, the radiating- spicular elements 

 are stouter and not on the same plane ; the consequence 

 is that the space between the contiguous side spicules 

 is not very distinct and sometimes it is clearly vacant, or 

 there may be a slight reticulation in parts. Lovdn con- 

 sidered that probably there are muscular fibres between the 

 side spicules of the four parts of the circlet in Toxopneustes^ 

 and although they are not visible in the specimens before me, 

 the possibility of their existence in fresh specimens is very 

 considerable j certainly these separate parts of the circlet 

 would be approximated by the contraction of the circular 

 fibres of the soft parts of the cup. 



Very few " C "-shaped spicules are present in the tentacles 

 of Temnopleurus, and I have only seen one instance of an 

 acerate spicule. 



The circlet of the cup of the larger and wider abactinal 

 tentacles is smaller than that of the actinal and is less 

 elaborately ornamented. 



Salmacis differs decidedly in the construction of its ten- 

 tacles from Temnopleurus, The abactinal tentacles are large, 

 long, baggy, and have small terminal cups ; the actinal have 

 Btout walls, are shorter, thicker, have a narrow calibre, and 

 the cup is large, fleshy, and the circlets are well developed 

 and very large. 



A circlet of an actinal tentacle has six or even seven divi- 

 sions, and each is as distinct as it is in Temnopleurus ; the 

 spoke-like processes are much more numerous and pointed, 

 and on the same circular line. The psellion is well developed, 

 and its accessory processes also. The central muscular struc- 

 ture is larger than in Temnopleurus^ and there are manj^ " C "- 

 shaped spicules all about the cup and the upper part of the 

 tentacle. The muscular structures are as in Temnopleurus. 

 Now the cup of the abactinal tentacles supports a very small 

 circlet, and its divisions are fewer in number than they are in 

 the actinal tentacles, but the " C "-shaped spicules are in 

 greater profusion, and the muscular layers are composed of 

 better developed circular fibres and very distinct longitudinal 

 ones. 



