Kellia.] PELECYPODA. 923 



shells. In many species the dental formula is not fully represented 

 by developed teeth. (Dall.) 



The genus is cosmopolitan. 



Fossil in the Tertiary. 



1. Kellia suborbicularis, Montagu, 180-i. Plate 63, tigs. 12, a. 



Mya suborbicularis, Mtg., Test. Brit,, 1804, 39, 564, pi. 2(5. f. 6. Kellia 

 'suborbicularis, Mtg.: Turton, Dithyra Brit., 1822, 57, pi. 11, f. 5, 6 : 

 Forbes and Hauley, Brit. Moll., ii, 1853, 87. pi. 18, f. 9; pi. 0, f. 4 : 

 E. A. Smith, Chall. Rep., xiii, 201 : P. Mai. S., v, 163 : Dall, Trans. 

 Wagn. Free Inst., iii, pt. 5, 1155. / Lepton faliagella, Conrad, Am. Mar. 

 Conch., ii, 1831, 53, pi. 11, f. 3. ? Montacuta Gouldii, Thompson, Am. 

 Journ. Conch., iii, 1867, 33, pi. 1, f. 15. Krycina rotunda, Deshayes, 

 P.Z.S., 1855, 181. Kellia rotunda, Desh., Chall. Rep., xiii, 202, pL 11, 

 f. 5. Erycina r.ycladiformis, Deshayes, Traite Elem. de Conch., pi. 11, 

 f. 6-9 ; P.Z.S., 1855, 181: Kellia cycladiformis, Desh. : Button, C.M.M., 

 75 ; J. de Conch., xxvi, 51 ; M.N.Z.M., 157 ; Melvill and Standen, 

 Scott. Nat. Antarctic Exp., 1907, 149. A', suborbicularis, Mtg. : Hedley, 

 P.L.S. N.S.W., 1905, 543. 



Shell small, ovato - subrotund, ventricose, thin and fragile, 

 moderately inequilateral, yellowish-brown, glossy, sometimes slightly 

 iridescent. Beaks rather prominent, inclined forward, small and very 

 acute, contiguous. Anterior end somewhat shorter than the posterior, 

 regularly or bluntly rounded ; posterior end broad, somewhat produced 

 below, rounded or bluntly sub-biangulated ; basal margin lightly 

 convex. Sculpture consisting of very fine concentric lines. Epidermis 

 delicate, glossy, yellowish - brown. Interior white, not shining. 

 Hinge : A large elongated triangular rather oblique resilium, situated 

 close under the beaks on the posterior side (interrupting the hinge - 

 margin, and causing, when removed, an apparent cavity in it). Right 

 valve with a single erect somewhat recurved primary tooth immedi- 

 ately under the apex of the shell, and a feeble secondary tooth in 

 front ; behind the resilium a second erect primary tooth and a faint 

 posterior lamella. Left valve with 2 adjacent primary teeth in front 

 of the resilium, the anterior tooth continued as a lamella in front ; 

 behind the resilium a primary tooth, sometimes obliquely erect and 

 ending in a short lamella behind. Adductor-scars rather large, ovate, 

 subequal, high up. Pallial line distinct, entire. 



Diameter Ant. -post., 13mm.; dorse-ventral, llmm.: thick- 

 ness, 8 mm. (a large specimen). 



Type in the British Museum. 



Hob. Bay of Islands ; Hauraki Gulf ; Banks Peninsula. Stewart 

 Island, in 18 fathoms ; Chatham Islands : from low-water mark to 

 about 60 fathoms. Also Tasmania, Australia, Kerguelen Island, 

 Burdwood Bank (in 56 fathoms), South Africa, British Islands, 

 Norway, Mediterranean, Massachusetts, Canary Islands, St. Helena, 

 Mazatlan, &c. 



