ACEPHALA TESTACEA. 10? 



PANOPEA, Mesnard* Lagr. 



A stout tooth, anterior to the callous enlargement of the preceding 



submenus, and immediately under tin- Mimmit, which <l<vu>sit<^ ;i 

 similar one on the opposite valve, a character which approximate the 

 Panopeae to the Solens. A large species is found in the hills at the 

 foot of the Appenines in so high a state of preservation, that it has 

 heen iiii>tak'ii for a recent sea-shell *. 



Tlit-rc is another fossil species, which may perhaps be separated 

 I'rum it. tliat is completely closed at its anterior extremity f. 



After these various modifications of the Myae, we may place the 



PANDORA, Bruy. 



In which one valve is much flatter than the other ; the internal 

 ligament is placed transversely, accompanied in front by a projecting 

 tooth of the flattened valve. The posterior side of the shell is elon- 

 gated. The animal withdraws more completely into its shell than 

 the preceding ones, and its valves shut more closely its habits how- 

 ever are the same. 



But a single species is well known ; it inhabits the seas of 

 Europe J. 



Here also we find a group of some small and singular genera, 

 such as 



BYSSOMIA, Cuv. 



Where the oblong shell, which has no marked tooth, has the opening 

 tor the foot at about the middle of its edge and opposite the summits. 

 The Byssomiae also penetrate into stone, corals, &c. 



A species which is provided with a byssus, abounds in the 

 Arctic Ocean . 



HIATELLA, Daud. 



The shell gaping, to allow the passage of the foot, near the middle 

 of its edges ; but the tooth of the hinge is better marked than in the 

 pp-ivding genus. Ranges of salient spines are frequently observed 

 on the hind part of the shell. They are found in sand, among Zoo- 

 phytes, &c. 



The North Sea produces a small species ||. 



* Myti ijlyrimeris, L., Chemn., VI, iii. A neighbouring, but shorter species in- 



iie Mediterranean. Another fossil species is found near Bourdeaux. 

 f l\ini>f <le Faujas, Mesnard, Lagr. Ann. du Mus., IX, xii. 



Urn- -houlil be the place of the SAXICAVA of M. F. de Bellevtie, small Testacea 

 u l.ich perforate stones. See Rois., VI, 44 1 . 



tlcis, Cheran., VI, xi, 106, and for the animal, Poli, II, xv, 7. 

 Mytilus pholadis, Mail., Zool., Dan., Ixxxvii, l, 2, 3, or Mya byssifera, Fabr., 



|| Solen minutus, L., Cbcmn., VI, vi, 51, 52, or Mya arclica, Fabr., Grcrnl., which 

 in tn he the same as the Iliat. & unefcnte, Bosc, Coq. Ill, xxi, 1 ; the lliat. 

 to, lil., Ih.. 2. 



