248 Die Silurische Fauna des Westlichen Tennessee, 



with Astylospomjia, with which, however, it has the common distinc- 

 tion of having no epitheca, on account of the gradual deflection of 

 its outer structure, and the larger- openings dispersed over the whole 

 surface. Thus there arose the necessity of creating a new genus, the 

 exact definition of which is, as yet, not clearly determined. Its name, 

 when settled upon, should indicate its similarity with the forms included 

 under the genus Manon, in the more recent formations. 



Genus Astrceosj)ongia — (Rcemer) . 



A globular-formed, unattached sponge, its surface and entire 

 mass filled with star-shaped bodies, which, though very regularly 

 formed, are dispersed without regard to any order ; but it displays no 

 distinct canals or pipes. 



The absence of an epitheca is as well determined in this genus as in 

 Adylospongia. Not a trace of an epitheca can be discerned in the 

 several hundreds of specimens of this singular geuus. In all of them 

 the lower part is uniformly flat or rounded. The body must have lain 

 simply with the flat lower side next the bed of the sea. 



The star-shaj)ed bodies, dispersed over the surface and throughout 

 the mass, are of a very different construction from the small stars that 

 appear in Astylospongia. They are, moreover, larger than the latter, 

 so much so that they appear upon- the most superficial inspection of the 

 sponge to the naked eye as noticeable bodies. Besides, they are 

 mutually unattached, and do not, like those of the Astylospongia, hang 

 together by their rays. The mass lying between the stars is wholly 

 shapeless, and presents neither openings nor any other organic texture. 



Astra'ospongia meniscus. — (R(emer). 



A round, globular-shaped body, concave at toj) and convex at bot- 

 tom, having its whole surface and entire inner substance filled with 

 regular six-rayed stars, dispersed about, in no particular order. 



This is, in several respects, a remarkable body, and owing to the 

 great number of the specimens, it is looked upon as one of the most 

 notable elements of the Fauna. Its most noteworthy mark consists 

 in the small star-shaped bodies which are always to be found dispersed 

 over the surface and in the substance of the body. They are formed 

 of six rays, resembling wheel spokes, with pointed ends, which always 

 intersect each other, at their centers, with remarkable and unexcep- 

 tional regularity, at an angle of 60 degrees. The size of the star is 



