74 



scythe-shaped but elongated S-shaped. The sigmatocoms are exceedingly fragile. 

 They measure about 150 /* in diameter, their branch-rays have a total length of 

 60-80 /^ , their scythe-blade-shaped terminal parts measuring about 15 m in length 

 (pi. XII, f. 18, 19). 



To the ends of the free projecting distal rays of the sword-shaped hypoder- 

 malia floricoms are attached, which do not essentially differ from the floricoms of 

 most other Buplectella-species. They measure 100 f* in diameter and each of 

 their main-rays generally bears 8 branch-rays, curved in the shape of an S. The 

 convex terminal discs on the distal ends of the branch rays have sharp margins 

 Avith five or seven small, pointed teeth (pi. XII, f. 3,4). Sometimes I found 

 floricoms, the terminal discs of which were only slightly developed and had a 

 smaller number of marginal teeth. In a few, only two teeth or spines were to 

 be seen at the ends of the branch-rays in. place of the missing terminal disc (pi. 

 XII, f. 6, 7). I cannot say whether these floricoms with only two terminal teeth, 

 which resemble the drepanocoms very closely, were, like the ordinary floricoms, 

 attached to the distal hypodermalia-rays, or whether they originally lay, like the 

 doubtless nearly allied drepanocoms, in the parenchyme, because I only saw a 

 few of them and these were not in situ. 



It is to be remarked that in young specimens of HexactinelUds generally the 

 hexasters with terminally thickened or disc-bearing branch-rays are, although of 

 equal diameter as those of full-grown specimens, much more slender, their main- 

 and branch-rays, and particularly the terminal thickenings of the latter, being 

 much thinner. It seems that all the radjal rays of the hexasters are at once 

 formed in their full length and that their later growth only leads to an increase 

 of thickness and to the local developement of lateral appendages. 



As only the upper part of the sponge is known I cannot say anything 

 definite about its mode of attachment to the sea-bottom. That both specimens 

 were torn off between the upper and central part of their length indicates, that 

 this sponge is, like Taegeria, Walteria and others, firmly attached ; and not loosely 

 planted in the silt by a root-tuft, like Euplectella, Holascus and others. I found, 

 however, in the lower part of the small specimen, one pentactine anchor with 

 four transverse, slightly recurved teeth, which formed a cross and contained 

 axial canals. The presence of this spicule might be supposed to indicate the 

 presence of a root-tuft. 



The upper, thickened margin of the sponge-tube is supported by stout 

 oxyhexactine principalia, the six rays of which are smooth, 60-100 a» thick and of 

 varying length. Their basal parts are regularly vertical to each other. Distally 

 they are either straight or curved in a peculiar and characteristic manner. The 

 lower paratangential ray, which extends longitudinally in the tube-wall and attains 

 a considerable length, and the two radial rays which remain short, are quite straight. 

 The two lateral paratangential rays are long and slightly curved in conformity with 



