84 CRETACEOUS PELECYPODA 



fio-s. 1-4). Prof. King strongly advocates the idea that Anthrucosia is a genus of the 

 JJmomBM, but there can be little doubt as to its close relation to Notomya, and it 

 is even very difiicult to distinguish between some of the species genericaUy. 

 The lio'amental area of Anthracosia much more recalls that of Panopcea and Cyrto- 

 daria than that of any known Uniosidje; and as Salter distinctly asserts that it is 

 a marine or brackish water shell, I think its classification in this place may be the 

 more correct one. The name Anthracosia has as yet been restricted to palaeozoic 



species only. 



3. Quenstecltia, Morris and Lycett, 1853, (MoU. Great Ool., pt. II, p. 96). 

 Shell oblong, equivalve, moderately solid, inequilateral, umbones nearly contiguous, 

 hino-e with a transverse cardinal tooth in the left and a corresponding pit in the 

 rio-ht valve ; ligament external, placed in a long narrow groove, pallial sinus small. 

 Only a few jm-assic species have as yet been referred to this genus ; its systematic 

 position is doubtful ; it is allied to the Saxicavid^ by its hinge and to the Anatinidm 

 by the form of its shell, and it may be considered intermediate between Saxicava and 

 Notomya in respect of its dentition. 



4. Faramya, Conrad, 1862 (?). Under this name Conrad introduces into the 

 family SaxicavidjE a small shell which he formerly described as Ilyulina suhovula 

 from the miocene beds of Virginia (see Proc. Acad. Phil., 1862, p. 572). The 

 species which has the general form of a Saxicava or of a Trapezium fCypricardia) 

 is described as possessing a small spoon-shaped, emarginated process in each 

 valve. It is not stated whether it indicates the presence of a cartilage or not ; 

 reference is made to the muscular and pallial impressions, but their form is not 



described. 



5. Saxicava, El. d. Bellv., 1802.* Shell elongated, rugose, posteriorly gaping, 

 anteriorly nearly perfectly closed, adult specimens have the right valve sometimes 

 laro-er than the left ; hinge with one tooth (occasionally two) in each valve, becom- 

 in"- sometimes obsolete in aged specimens, when the shells usually assume a great 

 thickness ; lio-ament small, not prominent ; pallial sinus moderate and often indis- 

 tinct ; — usually burrowing in stones and corals. 



The animal has the siphons separated at the end with fringed orifices, but is in 

 other respects very similar to that of Rocellaria. 



With regard to this genus it deserves to be noticed that the hinge-teeth do 

 not in all cases become obsolete with age, as often stated in the generic character 

 of this genus; several of our eastern species (S. similis and others) have them 

 - permanent and perfectly similarly formed to those of TanopcBa. 



* Ao-assiz and Herrmansen attach to i?7«/f/?a of Daudi n 1802 as the date of publication, and this would 

 sufficiently justify the adoption of the name Saxicava in preference to that of Hiatdla, simply because the former 

 name has become generally known and has already been introduced in all the larger conchological works. Cheiiu (Man. 

 II, p. 25,) gives the year 1799 as the date of p\ihlication of the name HiateUa, but I have not been able to find the 

 authority for this quotation. Deshayes (Paris foss., 2nd edit., I, p. Ki/.) gives 1801 as the year in wliich the name 

 ///a^e^Za was published, quoting as authority the " r histoire des coquilles" of Bosc, the same as cited by Agassiz 

 and Ilerrmansen. 



