CONCHIFERA. 725 
A. Monomyaria. Muscular impression single, subcentral. In- 
ternal ligament received in a cardinal pit, partially visible on the 
outside in some, mostly included. 
The single adductor muscle here corresponds to the posterior adductor of 
those conchifers that have two of them. All the single-muscled conchifers 
live in the sea. 
Family II. Ostracea. Mantle open. Foot none or a small 
rudiment of foot, not byssiferous. Shell irregular, lamellose. 
Anomia Brua. (Species of genus Anomia L.). Shell inequi- 
valve, thin, one valve flat, perforate or emarginate towards the 
point, the other larger, more gibbous at the base. Animal (Lchion 
Pout) with foot small, tentacles at mouth none, margin of mantle 
cirriferous, adhering to marine bodies by a muscular cord perforat- 
ing the shell and inserted into the calcareous cover. 
The name 4nomia was first employed by F. Cotumna (De Purpura, 
Rome, 1616) and given to those conchifera which are now named 
Terebratula. Linnmus united with these some very different con- 
chifers also under the name of Anomia, although what he says in the 
description of the characters of this animal (Sys. Vat., ed.12, 1. p. 1150) 
applies to Terebratula alone. Brucurire (Lncyel.méth., Vers. 1. p. 70) 
was the first who gave the name of Anomia to the present genus 
and placed it in the neighbourhood of the oysters. From these, 
however, it differs by many essential characters, so that DEsHAYES 
has placed it even in a separate family. There are properly three 
muscles of which the impressions are seen on the convex valve, but 
on the flat valve only a singular muscular impression appears. This 
impression is that of the muscle which corresponds with the central 
depressor of the oyster ; the two other muscles, which are attached 
tu the convex valve, go through the aperture of the flat valve and 
fix themselves to the calcareous cover, which is often very hard, 
whence it is named by several writers a little bone (ossiculwm). By 
that cover the shell is attached to other conchifera or to rocks. See 
Desuayes Dict. Univ. d’ Hist. Nat. 1. 1841, pp.557—559, and the 
figures of the three muscles in Pout Testac. wtr. Sicil. Tab. 30, fig. 
1, and in Cov. &. Ani., éd. ill., Moll. Pl. 79. 
Sp. Anomia Ephippium L., Lister Conch, 204, CHEMN. Tab. 76, figs. 692, 
693, Buainv. Malacol. Pl. 59, fig. 31, Cuv. R. Ani., éd. ill., Moll. Pl. 79; 
Mediterranean, Atlantic; this species is very flat, the shell is mostly of a 
whitish colour;—-Anom. cepa L., Pott Tab. 30, figs. 1, 8, is more convex, 
