182 CLASS II. BRACHIOPODA. FAMILY 2. ADH^RENTIA. 



PI. CXXVI. Fig. 2. 

 Terebratula caput-serpentis, Lamarck, Anim. sans vert., new edit., 



vol. vii. p. 332. Enc. Me'th., pi. 246. f. 7. a to/. 

 Anomia caput-serpentis, Linnaeus. 



PI. CXXVI. Fig. 3. 

 Terebratula dorsata, Lamarck, Anim. sans vert., new edit., vol. vii. 



p. 331. Enc. Meth., pi. 242. f. 4. a, b, c. 

 Anomia dorsata, Gmelin. 



PI. CXXVI. Fig. 4. 

 Terebratula rosea, Sowerby, Genera of Shells, No. 15. 



PL CXXVI. Fig. 5. 

 Terebratula psittacea, Lamarck, Anim. sans vert., new edit., vol. vii. 



p. 333. Enc. Meth., pi. 244. f. 3. a, b. 

 Anomia psittacea, Gmelin. 



Family 2. ADHiERENTIA. 



Testa statim affixa, valva inferiore pro transitu tendinis plerumque fissu- 

 rata. 



In this family the shell adheres immediately ; there is still, however, a 

 muscular tendon in most of them passing through a perforation or fissure 

 in the lower valve. The valves are not united by any ligament, nor do 

 they exhibit, except in the genus Thecidium, the cardinal processes or 

 internal skeleton so characteristic of the Terebratula. Their shell is for 

 the most part rather thin, and in composition may be said to be rather 

 horny than shelly. 



The Brachiopoda Adhaerentia are divided into three genera, as fol- 

 lows : 



Thecidium. Orbicula. 



Crania. 



