226 PROCEEDINGS OF THE ACADEMY OF [1887. 



Kespectfully dedicated to my friend Mr. Mills of Buffalo N. Y. 

 to whose perseverence as a collector we owe this and the following 

 beautiful species; the first new forms from the state of Florida; 

 besides specimens of S. fragilis, M. fluviatilis and H. ryderi at this 

 southernmost point of their range. 

 (10) Meyenia subdivisa, Potts. (PI. IX, fig. vi.) 



Sponge green when growing in the light, massive, encrusting; 

 texture compact; composed of thick lines of fasciculated spicules 

 and having a peculiarly vitreous, glistening appearance when dried. 

 Surface smooth or rising into moi'e or less abrupt rounded promi- 

 nences, near the extremities of which the efferent osteoles are found. 

 Pores numerous, conspicuous. 



Gemmules few, spherical, resembling in apj)earance those of the 

 genus Heteromeyenia; granular crust very thick. 



Skeleton spicules cylindrical, robust, abruptly pointed, smooth; 

 the smaller ones more or less microsf)ined. In many places at the 

 surface they gather into flocculent or wool-like masses, compactly 

 grouped, without interspaces. (See remarks on Tuhella pennsylva- 

 nica.) 



Dermal spicules absent or undiscovered. 



Birotulate spicules surrounding the gemmules very numerous ; so 

 crowded that some become displaced and, standing out beyond the 

 others, simulate the appearance of the longer class of birotulates in 

 Heteromeyenia. As all are of the same general shape however, and 

 nearly of the same size, it is thought best to retain the species in the 

 present genus. These spicules are very robust and the abundance of 

 silicious material is evidenced by the repeated subdivision of every 

 ray and spine. (PI. IX, fig. vi, e. e. e.) Shafts cylindrical, fre- 

 quently spined; rotules flat, irregularly circular, notched but 

 slightly at the margin. Short rays subdivided. 



Meas. Skeleton spicules O^Ol by 0"0006 inches. Birotulate 

 spicules O'OOIT by O'OOOo inches. Diameter of rotules 0'0009 inches. 



Hab. On submerged timber etc. 



Loe. Collected by Mr. H. Mills in St. John's River near Palatka, 

 Florida. 



Dr. Bowerbank has remarked (Proc. Zool. Soc. 1868, p. 443, 

 etc.) upon the number and variety of sponge spicules noticed by him 

 in a collection of infusorial earth, made by Prof Bailey in Florida; 

 and from this fact and the descri[)tions of other travellers it has long 

 seemed to me an ideally favorable place for the growth of sponges. 



