BY R. VON LENDENFELD, PH.D. 1139 



not open directly into the Gastral cavity, but coalesce by means 

 of short tangental tubes 6 to 20 of these coalesce to a very short 

 radial tube 0" I mm. in diameter, which opens into the Gastral 

 cavity with a trumpet-shaped extension. 



Spicules : The skeleton consists mainly of large Quadriradiates, 

 to which are added minutes Acerates in the cortex and tangental 

 Triradiates in the Gastral wall. The outer surface is covered by 

 a smooth cortex of a brilliant white color. 



The main part of it is formed of a cement of minute Acerates 

 which are pecidiar in shape. They consist of a longer conic and 

 pointed centripetal part and springing from the distal thick end of 

 this in an oblique direction a shorter also pointed centrifugal 

 part, which has the shape of a triangular pyramid. From the 

 edges of this pyramid strong spines take their origin, which are 

 as long or longer than the spicule is thick and give the edges of 

 the pyramid a strongly serrated appearance. These minute 

 spicules measure 0-06 x 0004 mm. In the cortex we meet here 

 and there with middle-sized Triradiates and large Quadriradiates. 

 The largest Quadriradiates are regularly disposed. Their rays 

 are sagittally developed. Three of them extend tangentally in 

 the outer surface, and lie in one plane, the fourth extends centri- 

 petally and is exactly radial in its position, standing vertical on 

 the plane of the other three. This centripetal ray is 1 1-5 mm. 

 long and straight. The tangental rays are 05 — 1 mm. long and 

 curved inward at the base. All rays are 0-06 — 08 mm thick. 

 These spicules are situated very regularly at equal distance. 

 Below the cortex a layer of Quadriradiates is met with, the sagittal 

 ra\ of which is situated centrifugally and meets the centripetal 

 ray of the dermal Quadriradiates. Parenchyma smaller trira- 

 diates regular, with rays measuring 0-2 — 05 x 002 — 0004 mm. 

 Parenchymal larger triradiate spicules with rays measuring 

 0-6 — 08 X 4-006 — 0-008. Between these regular spicules a few 

 irregular Triradiates are met with. Parenchymal Quadriradiates 

 irregular and variable, slightly smaller than the dermal ones 

 described above. Gastral and canal walls (exhalent) are coated 

 by a layer of sagittal triradiates, which are situated tangentally. 

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