243 



NATURAL HISTORY. 



VENUS YERRUCOSA, WITH ITS ANIMAL. 



ovate, and tumid, the valves grooved or lamellate; the margins of the shell finely crenulated ; the lunule 

 is distinct, the hinge thick, with three teeth in each valve; line of the mantle has a short angular bend. 

 One hundred and seventy-six species of this genus are found living, with a world-wide distribution, in the 



British Islands, North Sea, Mediterranean, Cape of Good 

 Hope, &c. They are found buried a few inches deep in 

 sand at low water, and range to 100 fathoms; they are 

 all edible. The North American Indians used to make 

 coinage ("wampum") of the sea-worn fragments of F. 

 mercenaries by perforating and stringing them on leather 

 thongs. Long Island was called Seawar hackee (or Shell 

 Island) by the Moheyan Indians, who resorted to it to 

 collect Seawan ("wampum shells"), from which they made 

 their purple beads. F. mercenaries ranges from Cape Ann, 

 Mass., to Delaware Bay; it is called the " round clam "- 

 "quahog." It sells from 37^ to 62J cents the bushel. 



Genus Cytherea. The shell is like Venus, but 

 the margins are smooth ; the border of the mantle 

 is plain, and the siphons are partly united. One hundred 

 and thirteen species are living. 



Genus Artemis. At first sight Artemis looks like a Lucina, but the outline is almost circular, 

 and it has a deep angular pallial fold ; the hinge is like Cytherea ; the foot is large and hatchet- 

 shaped ; the siphons are united ; the margin of the mantle is plaited. Artemis ranges from northern to 

 tropical seas, and from low water to 100 fathoms. One 

 hundred species are known. 



Genus Lucinopsis. The shell is less elegant in 

 outline than in Artemis, and thinner ; the right valve 

 has two diverging teeth, the left has three ; the mantle- 

 fold is very deep ; the siphons are longer than the shell, 

 and diverge from one another; their orifices are fringed. 

 Ten species are living in North America, Norway, the 

 Mediterranean, and Britain. It is also found fossil. 



Genus Tape*. The outline of the shell is ovate, ob- 

 long; the umbones of the shell turned forward; the margin smooth; the siphonal fold deep and 

 rounded. The animal is eaten in North America and on the coast of Europe ; it lives burrowed in 



the sand from low water to 100 fathoms. Nearly eighty species are 

 known living. 



The genus Venerupis lives in crevices of rocks ; the shell 

 is oblong and ornamented with concentric raised lamellae, and 

 striated radially. Twenty species are living in Britain, the 

 Canaries, India, Peru, &c. 



The genus Petricola burrows in limestone and mud ; the 

 shell is oval and thin. Thirty species are living in the United 

 States, New Zealand, <fec. 



Genus Glaucomya. The shell is shaped like a Mya, but with 

 three teeth in each valve. The siphonal fold is deep and angular ; 



the valves are covered with a dark green epidermis ; the siphons are very long. Twelve species are 

 living near the mouths of rivers in India, China &c. 



FAMILY XVIL MACTRID2E. 



The Mactridce have somewhat triangular equal valves, mostly close fitting ; they have a deep 

 pit for the hinge ligament, triangular in form ; the hinge has two diverging teeth ; the siphonal fold 

 is short and rounded ; the epidermis is thick. 



Mactra * has a large tongue-shaped foot ; the siphons are united and fringed ; the shell is 



* Latin, mr.ctrc,, a kneading trough. 



CYTHEREA GEOGRAPHICA, WITH ITS ANIMAL. 



CYTHEREA MACULATA. 



