CONCHIFEKA. 745 



Ungulina DAUDIN, LAM. 



This genus is much allied to Lucina, with which DESHAYES unites it. 

 Ungulina oblongalUAM., BLAINV. Malac. PL 73, fig. 6 ; from the coast of 

 Senegal. Since this animal penetrates stones and corals, the external form 

 of the shell is subject to much variety. See on the animal, of which pre- 

 viously the shell alone was known, DUVERNOY Ann. des Sc. not. sec. Sdrie, 

 Tom. 18, pp. no 122, PI. v. B. Comp. DESHAYES ibid. Tom. 19, pp. 

 5 ii. 



Corbis Cuv. Shell transverse, gibbous. Hinge with two teeth 

 under the point, and two lateral. 



Sp. Corbis fimbriata LAM., Venus fimbriata L., D'AKGENV. ConcJiyl. Tab. 

 21, fig. G, Encycl. meth., Vers. PL 286, fig. 3, BLAINV. Malac. PL 72, fig. 

 4 ; Indian Sea. This shell is finely striated longitudinally between grooves 

 running parallel to the margin. Hence the French name la Tricotee or la 

 Corbeille, of which last the generic name Corbis is a translation. There are 

 fossil species of this genus which are as finely or even more finely treliced. 



Family XVI. Saxicavina (or LitJwpJiaga}. Lobes of mantle 

 as to the greater part concrete, with aperture narrow, anterior, emit- 

 ting the small foot. Tracheae two, coalesced at the base, tentacu- 

 late at the opening. Shell transverse, inequilateral, posteriorly 

 elongate, gaping. Ligament external. Two muscular impressions 

 remote. Impression of mantle deeply sinuate posteriorly. (Animals 

 living in stones, hence the form of shell often irregular.) 



This small family is connected with the genus Venus on the one hand, 

 and with Gastrochcena on the other ; perhaps the genus Saxicava might be 

 placed in the last family. They are marine conchifers like all the following 

 families. 



Petricola LAM. (and Venerupis ejusd.) Hinge with two teeth 

 in each valve, sometimes with three. Branchia3 unequal, external 

 smaller. 



Venerupis LAM. Tracheae separate at the apex alone. Hinge 

 with three teeth in one valve, sometimes in both. 



Sp. Venerupis irus LAM., Donax Irus L., Encycl. me'th,, Vers. PL 262, fig. 

 4, POLI Test. utr. Sic. II. Tab. 19, figs. 25, 26; hab. Mediterranean; 

 Vener. perforans LAM., Venus perforans MONTAGU. (PHILIPPI has given a 

 figure of the Mollusc, see WIEGMANN Archivf. Naturgescli. 1845, Tab. vn. 

 figs. 1518.) 



Petricola LAM. Tracheae coalesced at the base, free at the 

 terminal part for nearly half their length. Hinge with two teeth 

 in each valve, or with only a single tooth in one of the valves. 



