242 ANATOMY AND PHYSIOLOGY 



FIG. 



87. SPICULATED EQUIANGULATED TRIRADIATE. When the 



spicular ray is of the same form and at right angles 

 to the common plane of the basal radii, from Leu- 

 conia nivea, Bowerbank. X 45 linear. Page 29. 



88. EQUIANGULATED TRIRADIATE: TJNIRADIALLYSPINED. 



I obtained a considerable number of this form of 

 spiculum from the dissolution in nitric acid of a 

 small fragment of a parasitical sponge, in the col- 

 lection of the late Mr. Charles Stokes. I have not 

 seen it in situ, but I have very little doubt from its 

 structure that the spiculated ray is a defensive one, 

 while the two spineless rays formed part of the 

 skeleton. X 130 linear. 



89. EQUIANGULATED SPICULATED TRIPODATE. When the 



basal radii are projected backward so that their 

 apices only are in the same plane, and the spicular 

 ray at right angles to that plane. The short spicu- 

 lar ray in this case is not based on a triradiate 

 skeleton one, but the whole speculum is essentially 

 a defensive one only. They occur in the lining 

 membrane of the cloaca of Leuconia nivea, Bower- 

 bank, and are very minute. X 660 linear. 



-. SPICULATED INEQUI-ANGULATED TRIRADIATE, WITH 

 CYLINDRICAL ENTIRELY SPINED RADII. See No. 

 234, and same number, Plate X. 



. SPICULATED ATTENUATO - EQUIANGULAR : VERTICIL- 

 LATELY SPINED. See No. 235, and same number, 

 Plate X. 



. SPICULATED CYLINDRO-EQUIANGULAR TRIRADIATE: 

 VERTICILLATELY SPINED. See No. 236, and same 

 number, Plate X. 



. INEQUI-FURCATO-TRIRADIATE. See No. 237, and same 

 number, Plate X. 



