148 
PALEONTOLOGY OF 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. 
5 6 
Fia. 5. Proddctella onusta. Fia. 6. Productella striatula. 
B C. Tooth-socket and socket plate. ( Enlarged to two diameters). 
J. Cardinal process. O. Anterior and posterior occlusors. V. The reniform 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). # 
* Productus longispinus and P. pustulosus have a similar form of the reniform impression. See David¬ 
son^ Monograph of British Carboniferous Brachiopoda. 
