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 

 sho\^^l ; and in the E. 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 Eriphyla it appears 

 to be a common occurrence. I find the Antillean shells presenting absolutely 

 the 8ame arrangement of teeth as the E. gregaria or E. umbonata. 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 Eriphyla 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 Eriphylopsis. 

 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 nmewed 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 Eriphxjla 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. 



