130 THE NAUTILUS. 



average of these three, given by such an authority, should satisfy the 

 most exacting. 



The average of the examples given by Simpson, gives a per- 

 centage of .556. The percentage which Rafinesque gives for 

 viridis (5 to U) is .555. 



A closer agreement is not to be found in the history of the Naiades ! 



Note The translation of Poulson contains many errors. 



1. The dimensions, one and a half inch is that of the altitude, 

 not as in Poulson. 



2. The lateral tooth is thin, not slender. 



3. The cardinal tooth is not divergent, but is decurrent quite 

 a different thing ! 



TTJBRITIDAE VS. TURRIDAZ. 



BY S. STILLMAN BERRY, 



The unfortunate rehabilitation of the nondescript names of 

 the Museum Boltenianum has brought about as one direct con- 

 sequence the overturning of the time-honored generic name 

 Plearotoma Lamarck in favor of Bolten's Turris. Accepting the 

 change as most seem to have been impelled to do, it thereupon 

 follows that since Pleurotoma was the typical genus of its family, 

 a change in the generic name necessitates a similar alteration in 

 the family name to conform. The reigning regulation in 

 Article 4 of the International Code of Zoological Nomenclature 

 is ostensibly so explicit regarding such matters as the formation 

 of family names that at first thought one would not anticipate 

 much disagreement among students in its specific application. 

 In the instance under consideration, however, two opposing 

 views have found t.ieir way into print. 1 Both cannot be equally 

 correct, and since the family is an abundant one and frequently 

 referred to, while a general principle of orthography is likewise 

 involved, it becomes a matter of some importance to determine 

 which of the two, as we may adopt the spelling Turritidae or 

 Turridae, is strictly the proper form to use. Curiously enough 



1 NAUTILUS, v, 23, pp. 131, 144. 



