CONCHIFERA. 753 



Panopcea M^N. LA GrR. Shell transverse, obtusely rotundate 

 at both ends, longer posteriorly. Hinge callous, with accessory 

 tooth in each valve. Impression of mantle excised posteriorly by a 

 sinus. 



Sp. Panopcea Aldrovandi MENARD, Mya glycimeris GHEL., CHEMN. Conchyl. 

 PI. 3, fig. 25, DESK. Conch. PL 7, fig. i ; in the Medit. Sea. A few other 

 living species of this genus are known; they are large bivalves that in 

 some degree resemble Mya. The fossil species occur in the chalk-formation 

 and more numerously in the tertiary, to which Panopcea Faujasii MENARD 

 belongs, according to DESHAYES merely a variety of Pan. Aldrovandi. 

 Comp. MENARD DE LA GROYE Ann. du Mus. ix. 1807, pp. 131 136, 

 PI. ix. and VALENCIENNES Archives du Mus. i. 1839, PP- I 33> P1 - * **. 



Family XXI. Solenacea. Mantle sacciform, open anteriorly, 

 with foramen for transmitting foot which is large, mostly truncated 

 at the apex, or terminated by a broad disc. Tracheae very often 

 conjoined. Shell equi valve, transverse, elongate, gaping at both 

 ends. Ligament external. Muscular impressions remote. 



Solan L. (exclusive of Anatina). Shell inequilateral, longer 

 posteriorly. Hinge with small teeth, two in left valve, one in 

 right received between the opposite teeth, or with single tooth in 

 each valve. Ligament elongate, often protuberant. 



Comp. L. SPENGLER STcrivter af Naturh. Selskabet. Kjobenhavn, 1793, 

 in. 2, pp. 8 1 114. 



Solecurtus BLAINV. (in part), DESK. Shell oval, rotundate at 

 both ends, subequilateral. Ligament large. Animal (Hypogcea 

 POLI) larger than shell, with foot large, Ungulate. Tracheae 

 long, conjoined at base into a wide pipe. 



Sp. Solen strigilatus L., POLI Test. utr. Sic. i. Tab. 12, 13, BLAINV. Malac. 

 PI. 79, fig. 4; in the Mediterranean. The fossil bivalve from the tertiary 

 formation, referred by LAMARCK to Solecurtus strigulatus (figured Ann. du 

 Mus. xn. PL 43, fig. 5) is, according to DESHAYES, a distinct species, Sole- 

 curtus Lamarckii. 



Solen DESH. Shell transverse, often very long, with hinge 

 sometimes almost terminal anterior. Ligament elongate. Animal 

 (Hypogcea POLI) with two short tracheae coalesced in most, in 

 some separate, with foot cylindrical, truncated. 



Razor-shell, Manches de Couteau, &c. The ancient names Solen, Aulos, 

 Donax (PLINIUS Hist. nat. Lib. xxxn. cap. 1 1), already indicate the most 

 common form of these shells. They hide in perpendicular holes in the 

 sands of the beach, whilst the tubes are turned upwards. Some species are 

 edible, and are much esteemed by the Italians, as Solen slliqua, according 



VOL. i. 48 



