ERYCINA. 



internal, attached in each valve to a narrow hollow space 

 between the teeth. 



Distinguished from Mactra, Crassatella and Lutraria 

 by the teeth and the position of the ligament, which, 

 although internal, is differently placed in Erycina with 

 respect to the teeth; it is a thick shell, and approaches to 

 Crassatella, but may be easily known from that by the 

 sinus in the impression of the muscle by which the mantle 

 is attached to the shell, and by the distinct compressed 

 lateral teeth. The Erycina are marine; we know of but 

 few recent species, but Lamarck has described nine fossil 

 species in the sixth volume of the Annales du Museum, 

 all of which are from the Calcaire grossiere, and in 

 M. Defrance's collection. 



As the three recent species we have represented, 

 have never been described as Erycinae, though we have 

 reason to believe two of them have been admitted by 

 Lamarck into other genera, we shall add the characters 

 of each species, and some observations upon one or two 

 of them. 



1. E. coniplanata, testa ovatii, compressA^, subinaequi- 



latera, Isevi, epidermide olivacea indut^, concolore. 

 Tab. nost. f. 1 . 



2. E. striata, testa a^quilaterti, subtrigond, com^ressa, 



costis plurimis, confertis, transversis, antice rigi- 



dis. Tab. nost. f. 2. 

 OZ>5.— This shell is figured in the Encyclopedic Me- 

 thodique, pi. 254, f. 4, to which Lamarck rel^rs for a 

 representation of his Crassatella striata; he does not, 

 however, seem to have observed the teeth, nor are they 

 shown in the figure ; but the external appearance is so 

 exact that we cannot doubt its identity. 



3. E.plebeia, testa oblonga, subcuneata, inaequilater^ 



coloribus variis radiata, latere antico brevi, sub- 



truncato. Tab. nost. f. 3. 

 Obs. — We believe this is the Crassatella cuneata of Lam. 

 V.p. 483, and the Donax plebeia oi English authors, none 

 of whom, however, seem to have noticed the internal 

 ligament, in which it difl*ers so essentially from Donax; 

 nor does Montagu's figure show the hinge of that shell: 

 the specimens we have seen are very variable in colour, 

 but they all have one or two radii diverging from the 

 umbo to the upper margin of the shell. It is figured by 

 Poli. vol. 2. pi. 19, f. 9, 10, 11, who calls it Mactra cornea. 



