KELLIAD^, 177 



lEREGULAE SHELLS, are those which, being attached to, or 



imbedded in other marine bodies, have no constant form, but are 



modified in shape according to the substances to which they are 



fixed, as the Chamacea, fig. 153 to 155. 



lEUS. Oken. Comprehending Pandoea, Petkicola, Saxi- 



CAVA, &c. 

 ISCHJS'OCHITON. G-ray. Chiton vestitus, and similar species. 

 ISOCAHDIA. Lamarck, 1801. (lo-oc, isos, similar ; Kapdia, 

 cardia, heart.) Fam. Cardiacea, Lam. Chamacea, Bl. — Bescr. 

 Cordiform, regular, equivalve, ventricose, with distant, diverging, 

 involute, free umbones ; hinge with two compressed cardinal teeth 

 in each valve, and one distant compressed lateral tooth; liga- 

 ment external, bifid, diverging in the direction of the umbones. 

 ■ — Obs. The shells composing this genus are remarkable for the 

 beautiful curvature of the diverging lunbones. European and 

 Chinese Seas, I. Moltkiana. PL vi. fig. 126. 

 KATHAEINA. Gray. Chiton lumiatus, &c. The external 



part of the shell is small. 

 KEEL. A flattened ridge, resembling the keel of a ship. As that 

 on the back of Carinaria vitrea, fig. 488, and those on the whorls 

 of some spiral shells. A shell characterized by a keel or keels 

 is said to be cariaated. 

 KELLLiD^. A family of small bivalve shells divided into the 

 following genera, viz. — 



MoNTACTJTA, Turtou. M. bidentata ? PL xxvii. fig. 570. 

 TuETONiA, Hanley. T.miuuta. PL xxvii. fig. 567. 

 Kellia, Montagu. K.. orbicularis. PL xxvii. fig. 569. 

 PoBONiA, Eecluz. P. rubra. PL xxvii. fig. 568. 

 LjiPTON, Turton. L. squamosum. PL iii. fig. 62. 

 G-ALEOMMA, Turton. G-. Turtoni. PL ii. fig. 58, 59. 

 With the exception of the two latter, the distinctions of the 

 above genera depend so much on anatomical grounds that our 

 readers must be content for the present vdth a characteristic 

 figure of each. 



Ptthina, Hinds, may be added to this family. PL xxvii. fig. 

 571. * 



