132 TELLINIDvE. 



Philippi, stated to be cirrhated at their apertures; foot not 

 very large, without byssal groove. Nothing is said in either 

 account of the branchiae, and Philippi only observes that the 

 animal has very "large oval palpi"; from which we hazard 

 an opinion that it may belong to our second section, in which 

 there is only one compound branchial lamina, and excessively 

 large palpi on each side of the body. In these extracts we 

 have a strict description of a true Tellinidan, of either the first 

 or second section. The teeth also are those of a Tellina, either 

 without or with obsolete laterals. Diodonta therefore is only 

 synonymous with a Tellina of one or other of the sections. 

 But if, from the very considerable variation of animal structure 

 in the two divisions, it should be thought advisable to con- 

 stitute a distinct genus for the second section, with the single 

 compound branchia on each side, and Diodonta should realize 

 our conjectures as to a similar form of the organs, it would 

 have priority over any other generic term, and in that case 

 would receive as congeners T. tennis, T. solidula, and perhaps 

 T. fabula. 



These are the reasons that have induced us provisionally to 

 deposit the T. fragilis in the second section, until we have 

 farther information on the required points. And we invite 

 naturalists who are in the vicinity of this interesting species 

 publicly to record their notes. 



LUCINOPSIS, Forbes and Hanley. 



The Venus undata of the older conchological authorities, 

 which has been justly separated from Venus by more recent 

 writers under various appellations, and particularly by the 

 learned authors of the ' British Mollusca ' under the title of 

 Lucinopsis undata, has given rise to much difference of opinion 

 amongst malacologists in regard to its natural position. 

 Though the shell of this species, anomalous in several points, 

 has long been known, the aggregation of the curious charac- 

 ters of its animal has never been sufficiently described, from 

 the difficulty of procuring it alive of large size. The quotation 

 from my manuscript in the ' British Mollusca ' is the result of 



