88 



and vertical to the surface. They are slender, smooth, rarely straight, usually 

 slightly curved and of varying length, often 3 mm. and more long, either 

 simply pointed and smooth or slightly inflated and rough or tuberculous at the 

 ends (pi. XXIII, f. 15-16). A more or less distinct annular thickening is often 

 observed in the centre of the spicule. 



I have not seen any hexactine macrosclere parenchymalia. 



The hypodermalia are stout oxypentactines with mostly straight or slightly 

 curved rays, pointed not very acutely, and rough near the ends, but otherwise 

 smooth. In some of these spicules the four paratangential rays are strongly 

 and uniformly recurved (pi. XXIII, f. 3), giving to them a form passing into 

 that of an anchor. It is to be noted that the large, freely projecting prostal 

 anchors (pi. XXIII, f. 14) mentioned above, are, apart from the difference in size, 

 similar to these pentactine hypodermalia. This leads me to suppose that the 

 anchors are to be considered as protruded and enlarged hypodermalia. 



The microsclere parenchymalia are slightly rough oxyhexactines with 

 straight rays, hemioxyhexasters and true oxyhexasters, all about 100 /* in diame- 

 ter. They lie in the well-known typical manner near the folded chamber- layer. 

 The most numerous of these spicules are the hemioxyhexasters. Their main- 

 rays are divided half way up into two branch-rays which accordingly are as long 

 as the main-ray and diverge pretty considerably. The branch-rays are uniformly 

 attenuated to the pointed ends, straight and rough. Sometimes only one of the 

 six main-rays is thus bifurcated, sometimes two or more. Not so numerous are 

 the forms in which all the six main-rays, and those in which none of the main-rays 

 are forked. The former appear as true oxyhexasters, the latter as true 

 oxyhexactines. 



Below the superficial membranes, in the subdermal as well as in the subgas- 

 tral trabecular regions, those exceedingly graceful hexasters, designated by me as 

 strobilocoms * are met with. These spicules, which I have also found in Lophoca- 

 lyx philippensis, SympagcUa nux and Galycosoma validum, measure 80 ^ in diame- 

 ter (pi. XXIII, f. 12, 13). 



The spined stauractine autodermalia exhibit the peculiar curvature in a 

 spherical surface, otherwise only met with in the stauractines of Lopliocalyx i^hil- 

 ippensis. They measure 150-200 i^ in length and their rays are distally rounded 

 and densely covered on all sides with short spines (pi. XXIII, f. 4-7). In some 

 of these spicules a fifth ray rises from the convex side of the crossing-point of 

 the other four. This ray is directed outward, cylindrical, quite straight, termi- 

 nally rounded and spined (pi. XXIII, f. 3, 4). In some of these pentactine 

 forms, as well as in some of the ordinary tetractine ones, an indication 

 of a radial ray directed inwards is present in the shape of a spined tubercle 



* Amerik-anische Hexactinelliden 1899 p. 29, Taf. IV figa. 3,4. 



