22 Prof. W. King on Spirifer cuspidatus. 
the use of the septum. The last of these points is of some 
importance; I may therefore be permitted to make a few 
remarks on it in the present place. 
Although the canaliferous septum, including that portion of 
the dental plates which serves, as it were, for abutments, has 
been compared with the arch-shaped chamber characteristic of 
Camarophoria, Pentamerus, and Stricklandinia, I have some 
grounds for disbelieving it to. be the homologue of the latter 
process. In Camarophoria and Stricklandinia, guided by the 
markings exhibited on some good casts of their chamber, and 
the absence of anything similar on casts of the pertaining 
valve, the muscles (their place in the genera mentioned is 
occupied by ovarian scars) to which reference has been made 
have undoubtedly been attached to the inner surface of the 
process*; but as these muscles in Spirifer cuspidatus have 
been fixed to the inner surface of the valve, the canaliferous 
septum must have supported some others. Can it have 
afforded attachment to the capsular muscle? In this case it 
might be concluded that the canal itself has served as a mus- 
cular fulerum for the dorsal pedicle-muscles, which ordinarily 
have one extremity implanted on the intercrural plate of the 
dorsal valve, and the other attached to the pediclef. 
Generic considerations. 
Although it has been shown that a number of Spirifers, in- 
cluding the type, Sp. striatus, are furnished with a canaliferous 
septum, I do not on this account consider that Sp. cuspidatus 
is a congeneric species ; for the apophysis in the former cannot 
be said to exist beyond a comparatively rudimentary condi- 
tion. Still I would not regard the more developed state of 
the canaliferous septum to be sufficient to constitute a generic 
distinction, were this appendage not associated with another 
important character. A perforated shell-tissue has been found 
in a number of species agreeing with Sp. cuspidatus in its 
apophysary system: I am therefore led to consider that the 
association individualizes a genus; and hence I am also led 
to adopt the name Syringothyris, which Prof. Winchell has 
appropriately applied to it. 
* It is the same with the saucer-shaped process of Leptena analoga, as 
I showed in 1850. (See precited Monograph, p. 75, pl. 20. fig. 6.) 
t+ In Cyrtia exporrecta, which has no canaliferous septum, another 
arrangement seems to have obtained. Judging from markings which I 
perceive in the proper place on some good casts before me of this shell 
from Connemara, apparently the dorsal pedicle-muscles were attached to 
the dental plates adjoining the foramen. 
