9S8 PALEONTOLOGY OF NEW- YORK. 



SUBGEIVUS AMBOCCELIA. 



In the Thirteenth Report on the State Cabinet*, I proposed the name 

 Amboc(elia as a generic designation for several species of fossils, of which 

 Orthis umhonata of Conrad was regarded as the typical form. This fossil 

 bears much resemblance to Spirifcr urii, Fleming ^ S. unguiculus, Phil- 

 lips ; but I do not regard the identity of the two as demonstrated at the 

 present time. The European species has been placed by Kino and M'Coy 

 under the Genus Mabtinia of the latter ; the typical species of which, 

 mentioned by M'Coy its author, are Spirifera decora, S. elliptica and S. 

 glabraf. These European species are not more nearly related to Orthis 

 umbonata than are some of our .own species, in which we observe the 

 ordinary characters of the Genus Spirifera., 



But there are a few points of distinction between these and the form 

 I have proposed to designate Amboccelia. Whether these are of generic 

 importance, may remain a question ; but they differ from those on which 

 the Genus Martinia was founded, and the allied species Spirifera urii = 

 . S. unguiculus was only included under the genus at a later periodj ; so 

 that if that one be proved generically distinct from Spirifera, it could 

 not supersede the type of the genus indicated by M'Coy. 



In the ventral valve, the thickened margins of the fissure are produced 

 in short strong teeth ; but there is scarcely any extension of the dental 

 plates into the cavity, or below the inner margin of the fissure. - 



In the dorsal valve, the bases of the crura continue attached to the 

 inner surface of the valve for more than one-third of its length, before 

 becoming free. There is a lateral projection from these crural bases, 



• Thirteenth Annual Report on the State Cabinet of Natural History, pp. 71 & 72. 1860. 



t Synopsis of the Carboniferous Fossils of Ireland, p. 139(1844). Mr. D a vinso.s', in his Monograph 

 of BritLsh Carboniferous Bracliiopoda, places S. decora as a variety of S. glabra, and S. elh'ptica as a 

 variety of S. lirtMita ; while Martinia oblata, M. ohlusa and M. symmetrica are regarded as simply 

 yarieties of Spirifera glabra, and Martinia mesohba and M. stringocephala as varieties of S. lineata. 



X British Palaeozoic Fossils, p. 377. 1855. 



