320 



NEW YORK STATE MUSEUM 



bellerophox Montfort. 1 808 (sensn stricto) 

 Bellerophon koeneni sp. nov. 



Plate 17, fig. 12-23 



Bellerophon striatus (Ferussac & d'Orbigny) ? Clarke, U. S. Geol. Sur. 



Bui. 16. 1885. p. 23 

 cf. Bellerophon tubercular us (Ferussac & d'Orbigny) d'Archiac & de Ver- 



neuil, Geol. Soc. Lond. Trans. 2. 1842. ser. v. 6, pt 2, p. 353; pt 28, fig. 9 



In the publication cited the writer noted the presence in the Styliola 

 limestone of a Bellerophon allied to the well known species of the Rhenish 

 middle Devonic, B. striatus. Additional material acquired since that 

 date indicates that it would prove unsafe to insist on identity in the species 

 here concerned. There are four typical Bellerophons besides B. koeneni 

 which we may specify, all of the same form and bearing surface characters 

 of close similarity but of some difference in combination. These are 

 B. striatus Fer. and d'Orb., B. tuberculatus d'Orb. of the Middle 

 Devonic, B. alutaceus d'Orb., lower Upper Devonic, and B. maera 

 Hall of the Chemung. These are all round and compact shells with but 

 slight apertural expansion (in this respect typical Bellerophons), and their 

 ornament consists either of tubercles without concentric striations or of a 

 combination of the two features. Thus B. tuberculatus and B. maera 

 are coarsely and regularly tubercled over all the surface, and in the latter 

 the slit band itself is sometimes broken up into such tubercles. In B. stri- 

 atus the concentric striae make themselves evident in crossing the tuber- 

 cles but not quite to the extinction of the latter. In B. alutaceus the 

 tuberculation is fine and the striae more obscure. In B. koeneni we find 

 in adult stages the tubercles, which are quite coarse, arranged with more or 

 less regularity in rows which converge backward to the slit band ; these 

 tubercles are often elongated in the direction of the row, and not infre- 

 quently adjacent ones are fused. Toward the peristome the very faint 

 concentric lines of the body of the shell become more sharply defined as 

 seal)' laminae, specially about the umbilicus. The slit band is narrow and 

 bears a succession of thickened festoons directed backward, but which do 



