148 



PALEONTOLOGY OP NEW-YORK. 



/■ 



LOsiA, I find evidence of a narrow area with small teeth and sockets in 

 the greater number of the species ; although these features do not usually 

 appear, except upon the most critical examination. The disposition of 

 the reniform vascular impression, however, does not correspond with 

 that of Strophalosia ; but in all the species where this feature has been 



observed, it is similar to that shown in figures 5 and 6. 



6 ' 6 



Fio. 5. Productklia oscsta. Fio. 6. Peoductella steiatula. 



B C. Tooth-socket and socket plate. ( Enlarged to two diameters). 



/. Cardinal process. 0. Anterior and posterior occlusors. V. The rcniforra vascular impressions. 



V. This letter refers to the faint diverging impression proceeding from the extremity of the mesial sep- 

 tum of P. onusta. A similar marking has been observed in another species, but no connexion with the 

 reniform vascular impressions has been observed. 



Neither of these species are known to have the/ apex of the ventral 

 valve truncated. In another species, with extremely gibbous and arcuate 

 ventral valve and deeply concave dorsal valve, the disposition of the 

 reniform impression is precisely like those illustrated ; and in none of 

 the species under investigation have we seen the least evidence of reni- 

 form impressions like those of figures 3 and 4, which are illustrations of 

 Permian species of Strophalosia. 



It is clear, therefore, that this character could not be relied on for 

 distinguishing the genus, if we were to include in it our Devonian spe- 

 cies ; for in the three species referred to, the imprint has the same direc- 

 tion and termination as shown in Aulosteges, except perhaps that the 

 muscular scars may be a little nearer the hinge-line ; and in this respect 

 it is not very dissimilar to some species of Productus,^ as shown in P. 

 costatus (figure 7).* 



• Productut longupinu* and P. pustuloiut have a similar form of the reniform impression. See Uavid- 

 •oa's Monograph of Brituh CarboniferoxuBrachiopoda. , 



