246 



PALEONTOLOGY OF ILLINOIS. 



In the residue left after freeing one of the specimens from the 

 matrix by means of acid, I found, beside the spicules above de- 

 scribed, a number of others, which could scarcely have belonged 

 to this sponge. Some belong to the genus Batospongia, founded 

 upon specimens from the same locality and supposed to be a 

 calcareous sponge. 



Another kind, represented in 

 the accompanying wood-cut, 

 is of regular Hexactinellid 

 form, and probably belonged 

 to a delicate sponge of the 

 ( type of Hyalostelia Zittel. 

 This supposition is strength- 

 ened by the fact that they 

 are associated with numerous 

 fragments of linear spicules or 



Fig. 1. A triflcl spicule of Hysti iospongia car- rods, fl'Om 0.07 to 0.12 Him. 



bonaria,*x 25. 

 Fig. 2. Small six-rayed spicule of Hyalostelia thick. The longest fragment 



delicatula, x 25. 



Fig. 3. one of medium size, x25. observed has a length of 5 mm. 



These spicules, being more slender and in all respects more 

 delicate than those of the several species of that genus known, 

 I propose to designate, provisionally, with the name Hyalo- 

 stelia delicatula. 



Position and locality: Near the base of the coal measures at 

 Seville, 111. 



BATOSPONGIA SPICATA n. gen. et sp. 



PL VI. Figs. 2-2a,2b. 



Sponge sub-hemispherical or sub-globose, consisting of small 

 in osculating sub-cylindrical or flattened branches, 0.5 mm. to 1.5 

 mm. in diameter, which arise from a reticulated basal portion, 

 and give the sponge a brushy appearance. In the perfect state 

 the base is covered with a dense dermal layer, which, when 

 separated, exhibits on its inner side a network of substellate or 

 irregularly branched spicule fibre. The meshes of the reticulated 

 basal portion of the sponge, (PI. VI, fig. 2,) vary in size from 



