Die Silurisclic Fauna des WcatUchen Tennessee. 251 



1 

 iving kinds seems to me to be analogcvus with the Silurian species 



Avhich we are describing. 



We shall now compare our species with the fossil described by Yon 

 Konig, under the title of BlumcnbacMum glohosum, one of the numer- 

 ous sponges described from other points of view. The author, in his 

 not very extensively diffused work, Icones fossilium seciiles, page 3, 

 describes it as follows : BlumenbacMum nob {Polypi corticaii). Poly- 

 pariura globosum, externe undique obsitum stellulis prominentibus 

 subquadratis, sa;pe confluentibus, punctato-porosis, interne caverno- 

 sum, substantia fibroso cellulosa. 



Blumenhachiian globomm n. Ex calcareo, ut videtur, transitionis. 

 Exemplaria duo in Museo Britannico asservata, indigena sunt; sed 

 locum natalem nondum compertura habemus. 



At first sight the description and representation of the figure 

 appeared to me to so accurately resemble the fossil of Tennessee, that 

 I referred the latter to the same genus, and described it under the title 

 of BlumenbacMiim meniseus. But the more recent description and 

 representation of the Blumenbachiuni globosum by Lonsdale, in Mur- 

 chison's Silur. Syst. II., 680, plate 15, fig. 26, in which it is placed 

 under the head of Bryozoa, shows that it is wholly distinct from the 

 American fossil. Moreover, Morris Catal. of Brit. Foss., 2d Ed., 1854, 

 p. 129, places this species as synonymous with the Theonoa globosa, 

 Vv'^ood (Am. Nat. His., vol. xiii., p. 13), under the Bryozoa, taken from 

 the crag of Suffolk. As it is to be presumed that the last named English 

 author saw the original specimen of Konig, the relationship which I 

 had previously referred with the American fossil falls to the ground. 



On the other hand, the Acanthospongia silmiensls, described by 

 McCoy (Synops. of the Silur. Foss., of Ireland, Dublin, 1846,-67), 

 and taken from the Silurian strata at Cong, in the County of Galway, 

 seems to be related to the Astraiospongia. According to description it 

 forms an oval body, fwo inches in length, filled with spiculi?e, in the 

 form of a cross (X), and from two to six lines in width. 



Occurrence — This species is the most frequent fossil of the Fauna, 

 and I have, myself, collected several hundred specimens. I found 

 them to be most frequent in the neighborhood of Brownsport, near 

 Mound Glade. On Bea:r Grass Creek, too, near Louisville, this species 

 is to be found in strata of the same age, but less well preserved. 



Theocostegites Heniisjyhcericiis — (Rcemek). 



A semi-circular polypidom of from one to two inches in diameter, 

 having its entire upper surflice covered with small cellular openings, 



