258 BULLETIN OF THE 
chology, Vol. III. p. 226, under Eriphyla, and of course gives an entirely wrong 
idea of Eriphyla, which has no pallial sinus, or at least none has ever been 
shown; and in the £. gregaria there is a perfectly simple pallial line, as in the 
recent species I have referred to. 
Now it is well known that in Astarte it occasionally happens that the teeth 
may be reversed with regard to the valves. In the allied Hriphyla it appears 
to be a common occurrence. I find the Antillean shells presenting absolutely 
the same arrangement of teeth as the EF. gregaria or E. wmbonata. E. mac- 
tracea, however, seems to have the teeth the other way generally; but not 
invariably, if I have correctly identified some valves from the Florida coast. 
A little groove behind the beaks is often there, too, but it does not carry any 
external ligament, and as the existence of an external ligament was based 
merely on the presence of this feature (which varies more or less between differ- 
ent specimens), it is evident that there is no warrant for claiming an external 
ligament for Eriphyla any longer. Meek, both in his publications and in con- 
versation, was confident of the identity of Hriphyla with the so-called Gouldia, 
if it could be shown that the teeth in the latter were reversible ; but at that 
time, just before his death, we had but a few specimens of the recent forms 
which did not seem conclusive, as they were all of the C. mactracea. So, in 
his last revision of his Paleontology, he suggested that, if the Californian and 
Missouri fossils did not agree, the latter might take the name of Hriphylopsvs. 
The recent Antillean forms, as I have said, agree perfectly with Eriphylopsis, 
and there is every reason to think that they agree with the original Eriphyla ; 
which, until a difference is definitely shown by renewed observations, I prefer 
to retain. Should any differences be found, the recent forms would follow the 
Missouri fossil and be included in the subgenus Eriphylopsis. 
That these little shells present a recognizable facies sufficient to enable one 
to decide instantly whether any one of the species is an Eriphyla or a typical 
Crassatella is, I think, undeniable. Whether this facies—of which the im- 
portant features are the small size, triangular form, inequality of the valves, 
absence of rostration, and the angulated posterior extremity — is sufficient to 
entitle the group to a name, I am quite willing to leave to others to decide for 
themselves. It seems to me they are, and that the distinctions are just as clear 
between Hriphyla and say Crassatella nana, as if one of the larger Crassatellas 
had been chosen. 
The fact of the inequality of the valves has been questioned, but I have 
never seen a perfect pair in which, looking forward over the beaks, the right 
valve did not advance above the other; the contrary being the case in looking 
the other way, though not so well marked. In convexity they are about equal. 
This is also true, but much less perceptible, in Crassatella proper. 
I have gone into the matter at this length because, it seems, I was insuffi- 
ciently detailed in my previous statement ; not making myself fully under- 
stood by some, who were unfamiliar with the errors of Gabb and Stoliczka. 
