FAMILY CANCELLARIIDjE. 



In the "Structural and Systematic Conchology," ii, 180, I 

 have given diagnoses of the family, of the genera Cancellaria 

 and Admete, and of the several subgenera. The latter, as far 

 as the recent groups are concerned, are the same as given by 

 H. arid A. Adams in their " Genera of Recent Mollusfca," a 

 classification mainly original with those authors. Several fossil 

 subgenera are also described and illustrated in my above-named 

 work, and need not be reproduced here; among the present 

 illustrations, however, will be found one of a lingual tooth of 

 Admete, as a type of the dentition of the family (PI. 7). 



As is frequently the case with the subgenera of Messrs. 

 Adams, the study of extensive suites of species of Cancellariidse 

 proves these to possess little value for classification. Dr. Paul 

 Fischer in his excellent u Manuel de Conchyliologie " has recog- 

 jiized this fact, and has reduced several of these subgenera of 

 Messrs. Adams to the rank of sections. 



Fischer proposes the following classification : 



Subgenus CANCELLARIA, s. stricto. Shell cancellated, aper- 

 ture oval, canal very short ; columellar plications nearty central, 

 strong, oblique (G. cancellata, Linn.). 



Sections, I. EUCLIA. Shell smooth (G. solida, Sowb.). II. 

 NARONA. Shell cancellated, basal canal rather long (C. Milrae- 

 formis, Sowb.). III. MASSYLA. Shell fusiform, retracted in 

 front ( C. corrugata, Hinds). 



Subgenus MERFCA, H. and A. Adams. Shell oval, whorls 

 reticulated; aperture oval, lip not contracted in front, columella 

 obliquely truncate at the base, imperforate (C. melanostoma, 

 Sowb.). The subgenus APHERA only differs by its thicker lip 

 and more spreading columellar callosity (G. tessellata, Sowb.). 



Subgenus TRIGONOSTOMA, Blainv. Shell widely umbilicated, 

 whorls angulated, aperture trigonal, lip not contracted in front 

 (C. trigonoxtoma, Desh.\ The genus Turbinopsis, Conrad, 

 differs from Trigonostoma in having a single basal plication of 

 the columella. 



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