HISTORICAL NOTES. XXV11 



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 Urocoptida, in their masterly 

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

 Cylindrellidae et de quelques genres voisins sous le rap- 

 port conchy liolo gique, " 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 Berendtia, 

 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 

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

 drellidce 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 : 



Cylindrellidcz. 



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. (Coclocentrum was defined, 

 but not named until later). 



