248 ANATOMT AND PHTSIOLOGY 



Pig. 



119. BiCLAVATB BiHAMATE. — There is a considerable varia- 



120. tion in the shape of this spiculum. The form 

 represented by Fig. 119 is perhaps the most numer- 

 ous, but that of Fig. 120 is the largest and most 

 fully developed. X 1060 linear. Page 44. 



121. BiCALCARATE BIHAMATE. X 1250 linear. — This 



singular and minute form of spiculum has hitherto 

 been found only in Isodictya Normani, Bowerbank. 



122. QuADRiHAMATE. From Hyalonema mirabilis. Gray. 



X 1250 linear. — ^They are dispersed in considerable 

 numbers on the interstitial membranesof thesponge. 



123. Unipocillated bihamate. X 1060 linear. — One 



termination fully developed in the form of a cup, 

 while the other is only produced to the extent of 

 the two lateral curves, and a terminal umbo to the 

 shaft. HaHchondriaHyndmani^awerh&Vik. Page44. 



124. Simple bipocillated bihamate. — X 1060 linear. 



Having both terminations developed in the form of 

 cups in coincident planes. Halichondria Hynd- 

 mani, Bowerbank. Page 44. 



125. Contort BiPQCiLLATED bihamate. X 1060Hnear. — 



Two cups being developed, but in planes at right 

 angles to each other. Halichondria Hyndmani, 

 Bowerbank. Page 44. 



126. Umbonated bipocillated bihamate. X 1060 



linear. — Having a slight prolongation of the shaft 

 through the distal edge of one or both of the cups ; 

 in this case through the distal edge of the lower 

 one only. Halichondria Hyndmani, Bowerbank. 

 Page 29. 



127. A view in profile of a unipocillated spiculum, X 1060 



linear : the upper part of the figure represents a 

 side view of the cup, while the termination of the 

 lower portion is more than usually elongated ; 

 showing how the umbonation is produced on 

 the distal edge of the spiculum, represented by 

 Fig. 126, Halichondria Hyndmani, Bowerbank. 

 Page 44. 



