80 PECTIXID.E. 



could scarcely be distinguished from Limopsis. The 

 species which he noticed were five in number, viz. two 

 from the lias and lower oolite, and three from tertiary 

 strata. But in giving the Ostrea strigilata of Brocchi 

 as the type of his genus Limea, he seems to have mis- 

 understood the Italian geologist, who nowhere mentions 

 the hinge of his shell being toothed. The words used 

 by him are. " II margine delle valve comparisce cre- 

 nellato tutto all' intorno ; il cardine non e obbliquo come 

 nella precedente Ostrea tuberculoid, Olivi) ma sibbene 

 retto, e nelF area del legamento si scorge una fossetta 

 trasversalmente bishuiga." Brocchi'a species belongs 

 to the section which comprises our L. Loscomhii. Loven 

 adopted Bronn's genus for L. Sarsii, considering it to be 

 a passage towards Umopsis, and says that the mantle of 

 the animal has no cirri ; but Sara, in his account of the 

 Arctic Mofluaca on the coast of Upper Norway, has 

 since observed that the mantle of this species is like 

 that of the rest, and set with proportionally large ten- 

 tacles or cirri which are thick and ringed, although not 

 particularly numerous. According to Searles Wood, 

 . . of his specimens of L. mbauriculata from the Crag 

 have the hinge-plate minutely crenulated. The same 

 character is seen in many species of Peeten. T 

 crenulations probably serve for the firmer attachment 

 of the cartilage to the hinge-plate, and not for a separate 

 fastening as in the interlocking teeth of Area. They 

 are too slight for the last-rnentioned purpose. Norwe- 

 gian specimens of L. Sarsii are much larger than ours. 

 This and the next two species form a distinct section, 

 which Klein more than a century ago called Ctenoides, 

 and for which Searles Wood has proposed the subgenus 

 Limatula. 



