248 PALEONTOLOGY OF ILLINOIS. 



BELEMNOSPONGIA nov. gen. 



Sponges free (?), composed of elongate acerate spicules, which 

 radiate upward and outward from a pointed base. The spicules 

 are large, sub-equal and joined to each other by short processes, 

 while they tend to arrange themselves into fascicles. 



I am not acquainted with any genus of this order of the 

 sponges from which Belemnospongia is not distinguished by the 

 large size of the spicules, coupled with their tendency to become 

 fasciculate, and in being united to each other by short lateral 

 processes. 



In a letter to the author, Dr. Hinde suggests that this genus 

 might be compared with his Climacospongia. During the past 

 summer (1886), I made extensive collections of the sponges 

 from the Niagara group of Tennessee, and among them I found 

 no difficulty in detecting several specimens of C. radiata. Upon 

 careful examination I find that instead of belonging to the 

 Monactinellida, as asserted by Dr. Hinde, Climacospongia is a 

 real Lithistid, comparing favorably in the arrangement of the 

 spicular mesh with the Anthaspidellidre, to which family I pro- 

 pose to refer the genus. 



BELEMNOSPONGIA FASCICULARIS n. sp. 



PL III, fig. 2, 2a, 2b. 



Sponges consisting of rather large acerate spicules, that radi- 

 ate upward and outward to form a loose sub-hemispheric or 

 discoid mass, with the base pointed, and the centre of the upper 

 surface depressed. The spicules are straight, cylindrical, taper- 

 ing gently to both extremities, 4 mm. to 8 mm. in length, 0.18 

 mm. in diameter, and united to each other by a small number 

 of lateral processes, exhibiting at the same time, a more or less 

 marked tendency to arrange themselves into bundles of three 

 or more. At the surface of the best example the spicules are 

 as a rule, smaller than those in the inner portions of the skele- 

 ton. 



The specimens are preserved in chert nodules, and in all, save 

 the one figured, the spicules have been dissolved and removed, 

 leaving only the empty moulds. As is shown by a fracture, 



