150 LEtrCOZONIA. 



Subgenus LATIROLAGENA, nom. mut. 



Lagena, Schumacher, Essai jS'ouv. Syst. Habit. Testaces, 1817, 

 p. 240; non Walker and Boys, 1784; non Bolten, 1798. 



Distinguished from typical examples oi Leucozonia by the absence 

 of keels on the whorls, the latter being rounded ; the shell is 

 bucciniform and devoid of conspicuous ornament, whilst the 

 denticle or tubercle (when present) on the outer margin is 

 extremely rudimentary. 



The name Lagena, Schumacher, commonly employed, is pre- 

 occupied by that given to the well-known genus of foraminifera 

 by Walker and Boys, and it refers also to one of the Tritonidse, 

 if Bolten's work is to be accepted. Plicatella, Swainson ' {non 

 Schmidt, 1870), is sometimes alluded to as being synonymous 

 with Lagena, but the first species mentioned by that author as 

 ascertained on reference to the work he quotes,^ is Fusws polygonus, 

 Lamarck (erroneously given as ^^ polyzona'" by Swainson), and 

 that has been selected by Dr. Gray^ as the type of Plicatella. 

 Swainson substituted the last -mentioned name for Polygona, 

 Schumacher,* rejected on account of being preoccupied in Botany, 

 which, however, is not a valid ground for exclusion following the 

 rules of nomenclature as usually interpreted at the present day. 

 If, therefore, we have recourse to Polygona, we find on reference to 

 the type quoted by Schumacher that that generic name could 

 not possibly apply to such forms as he included in the genus 

 Lagena. The Lagena of Klein,^ being pre-Linnean, ought not to 

 be recognized. Under these circumstances the present writer 

 cannot, in suppressing Lagena, Schumacher, utilize either Polygona 

 or its synonym Plicatella, and now suggests the name Latirolagena 

 instead, as indicating its affinities with Latirus. 



It is related to Mazzalina, Conrad, but the type of that genus 

 {M. pyrula, Conrad) is strongly plicate, the several plaits being 

 implanted obliquely on a profoundly excavated columella ; that 



' Malacolojjy, 1840, p. 304. 



^ Ency. Meth. pi. ecccxxiii. fig. 1. 



3 Proc. Zool. See. 1847, p. 136. 



* Essai Nouv. Syst. Habit. Testaces, 1817, p. 241. 



* Ostracologicse, 1753, p. 49, tab. iii. No. 01. 



