HISTORICAL NOTES. XXvii 



series of works since Ferussac. The number of species 

 had been largely augmented; numerous groups had been 

 established; but they were based upon mere external form 

 and general appearance of the shell, and hence were for the 

 most part artificial and heterogeneous. 



II. 



It was in 1870 that H. Crosse and P. Fischer inaugurated 







the scientific classification of Urocoptidce, in their masterly 

 paper, "fitude sur la machoire et 1 'armature linguale des 

 CylindrellidaB et de quelques genres voisins sous le rap- 

 port $onchyliologique, ' in the Journal de Conchyliologie, 

 xviii, pp. 5-27. They demonstrated that two widely 

 diverse types of jaw and teeth occurred in the assemblage of 

 species formerly referred to Cylindrella. On the one hand, 

 Holospira, and the new genera Eucalodium and Bcrcndtia, 

 have a jaw sculptured with vertical riblets, folds or striae, 

 and a wide radula, with horizontal rows of teeth resembling 

 those of Helix. These forms they referred to the family 

 Helicidcc. On the other hand, those left by them in Cylin- 

 drellida? were found to have an extremely thin jaw, made up 

 of narrow plaits, converging to form a chevron in the middle ; 

 the radula is longer and composed of oblique series of teeth 

 of a special peculiar shape. The following classification is 

 proposed : 



Cylindrellidce. 



1. Groupe A. Cylindrella Pfr. (= ; Brachypodella and 

 Tetrentodon). 



2. Groupe B. Callonia C. & F. (C. elliotti, now placed in 

 Urocoptis) . 



3. Groupe C. Thaumasia Alb. (Urocoptis of Jamaica and 

 Cuba) . 



4. Groupe D. Lia Alb. (=Anoma). 



5. Groupe E. Macroceramus Gldg. (M. signatus, etc.). 



Helicidce. 



1. Genre Eucalodium C. & F. (Ccclocentrum was defined, 

 but not named until later) . 



