260 ANATOMY AND PHYSIOLOGY 



FIG. 



195. CORONATO-HEXRADIATE STELLATE. From a Species 



of Alcyoncellum in the Museum of the Jardin des 

 Plantes, Paris. X 1060 linear. The central 

 radii consist of six rectangulated primary rays of 

 equal length, each terminating in a discoid expan- 

 sion, the margin of which is furnished with numer- 

 ous curved petaloid radii. 



196. POCILIATED HEXRADIATE STELLATE. X 1060 linear. 



The central radii consist of six rectangulated pri- 

 mary rays of equal length, each terminating in a 

 concavo-convex disc or cup, the convex surface 

 being outward. 



I found this extremely minute form entangled in 

 the tissues of a specimen of Halichondria incrusfans, 

 dredged up by my friend Mr. McAndrew at the 

 Orkney Islands, and it is probably from one of the 

 small species of Alcyoncellum that are found in the 

 North Sea. 



197. DENTATO- CYLINDRO- HEXRADIATE. X 660 linear. 



(See Plate X.) From a unique and very beautiful 

 branching sponge from Nichol Bay, Australia, sent 

 to me by my friend, Mr. Geo. Clifton, of Free- 

 mantle. The dentation of the radii of these spicula 

 varies considerably in form and size ; the number 

 of teeth at the apices of the rays is usually two or 

 three, occasionally four, and very rarely five. The 

 spicula are nearly uniform in size and are ex- 

 tremely abundant in all parts of the interstitial 

 membranes. 



198. ATTENUATO-RECTANGULATED TRIRADIATE : APICALLY 



SPINED. X 90 linear. This form is not, as it 

 might be hastily surmised, the triradiate stage of 

 development of a hexradiate spiculum. It is 

 larger in every respect than the slender variety of 

 the hexradiate form, and less stout, but much 

 longer than the stout variety of the hexradiate 



