242 PROCEEDINGS OF THE ACADEMY OF [1887. 



(4) Heteromeyenia longistylis, Mills. Proc. Am. Soc. of Microscopists 1884 ji. 16. 



Sponge unknown. 



Gemmulse large, spherical ; crust thick. 



Skeleton spicules slender, cylindrical to sub-fusiform; gradually 

 pointed, very sparsely microspined. 



Dermal spicules fusiform, entirely spiued ; spines near the mid- 

 dle long, cylindrical ; terminations rounded. 



Shafts of the larger class of birotulates relatively very long, cy- 

 lindrical, often bent, generally smooth. Hooks of rotulre recurved 

 and incurved. 



Rotules of the shorter class of birotulates flatter ; shafts cylindri- 

 cal, spinous ; spines short, conical. 



3Ieas. Skeleton spicules O'OIOB by 0'00025 inches. Length of 

 dermal spicules 0-0023 inches. Long birotulates 0-0049 by 0-00015 

 inches. Diameter of disk 0-0009 inches. Length of short birot- 

 ulate 0-0032 inches. Diameter of its disk 0-0008 inches. 



Loc. Lehigh River, Bethlehem, Pa.(?) Collected by Dr. Wolle. 



I had been inclined to consider the above merely a variety of 

 S. argyrosperma, but the mention of dermal spicules in my descrip- 

 tion, prepared several years ago from a very minute fragment, has 

 induced me to give it the benefit of the doubt, until the sponge 

 itself can be again collected. 



(3) Heteromeyenia ryderi, Potts. Proc. Acad. Nat. Sci. Phila. 1882, p. 13. 

 (PI. XI, fig. iv, V and vi.) 



Sponge light green, massive, often hemisi^herical ; texture loose » 

 surface more or less lobed. 



Gemmulse numerous, spherical, relatively smaller than in H. argy- 

 rosperma; crust thick; foramina inconspicuous, short, tubular. 



Skeleton spicules non-fasciculate, fusiform, gradually pointed, 

 entirely spined, except at the extremities ; spines broadly conical, 

 often projected forward, towards the terminations of the spicules. 

 (PI. XI, figs, iv to vi, a,a, etc.) 



Dermal spicules wanting. 



Long birotulates variable in relative numbers, shafts cylindrical, 

 spined ; spines equal in length with the rays of the rotulse ; hooked 

 or curved from the extremities ; rotulre of three to six short, re- 

 curved hooks ; sometimes umbonate or with a spinous termination. 

 (Ibid. b,b, etc.) 



Short birotulates with cylindrical shafts rapidly enlarging under 

 .the rotules, bearing one or more perpendicular spines. Diameter 



