2fii, CRETACEOUS PELECYPODA 



There is no douLt that Lamarck, when he first proposed his genus Erycina, 

 also referred to it species which have been afterwards shown not to belong to it. 

 The greatest objection made against Lamarck's name is the association of some 

 SiindosmycB with it, both genera agreeing in several important characters. At 

 the same time there can, 1 believe, be not the least doubt that Lamarck has 

 taken his original characteristic from one of the typical species which he described, 

 lor he mentions nothing of the existence of a pallial sinus. This character was 

 afterwards added in the subsequent edition of the An. s. Vert. Deshayes, 

 therefore, justly says in his second edition of the Paris fossils that Lamarck's 

 ori'^inal characteristic Avas an excellent one; and certainly the description of 

 the hin"'e Lamarck gave covild not be misunderstood for anything else but an 

 Erycina. Lamarck could not have taken his characteristic from any living species. 

 Weinkauff (Conch, d. Mittelmeeres, 18G7, p. 180,) discussed the propriety 

 of the two names Erycina and KelUa, and says, that if the former is to be retained 

 at all it should be restricted to the fossil species only, but where no essential 

 differences exist, no generic distinctions can be made. Chironia which was 

 proposed by Deshayes for the recent Erycina Laperoitsil, and which is adopted 

 bv Chenu in his Manuel, has been agaia identified by Deshayes wdth the present 

 o-envis. It docs not off'er any distinctive characters from Erycina. 



2. Erycinella, Conrad, 1838, (Mioc. foss., p. 74). Shell minute, oval, with 

 di"-htlv produced, obtuse beaks, inequilateral, surface with indistinct radiating 

 lines- hino'e in the left valve with two small inner and two large outer cardinal 

 teeth, ri"-ht valve wdth only two outer large teeth ; cartilage apparently in an 

 internal "-roove between the teeth, but it is not specially referred to in the type 

 species E. ovalis, C, which is from miocene beds of Virginia. Conrad's character- 

 istic is not very satisfactory, and (Am. Journ. Conch., v, 102,) he says that 

 the olio-ocene TFoodia Icevigata from Sollingen (Dunker's Palajiut., vi, 252, 

 T)l. 30, fio". 8,) is an Erycinella. If this be the case no cartilage would seem 

 to be present, but only a single median cardinal tooth, and the outer cardinals 

 shouM then be looked upon as laterals, in which case Erycinella should be 

 transferred to the Astartibm and placed near Woodia, if not identified with it. 



3. SpaJiiodon, Reuss, 1867, (Sitzungb. Akad., AVien, Iv, p. 134). Shell 

 roundlv sub-trigonal, with somewhat produced obtuse beaks, nearly equilateral ; 

 surface only concentrically striated; hinge with an anterior (sub-lunular) elongated 

 cardinal tooth in each valve, in the right separated from the margin by a deep 

 o-roove • cartilage in a pit situated below and a little posterior to the beaks ; mus- 

 cular impressions rather large, equal. Type, Sp. nitiditu, Ess., from miocene 

 beds near Wieliczka in Galicia. 



4. Montacula, Turton, 1819. Shell minute, oblong, inequilateral, radiately 

 striated or obsoletcly sulcated ; hinge with two remote, diverging cardinal teeth 

 in each valve, cartilage situated internally between them. Type, M. sub-striata, 

 Mont. Thomson described a M. Gouldi from America (Am. Joui-u. Couch., iii, 

 p. 33). 



