219 



slight in some species, and it sometimes happens that one might 

 easily assign the same species to one or the other, according to the 

 stage of growth which it has attained." Having regard to the 

 opinion of this distinguished conchologist, I have made my com- 

 parisons among species of the genus in its widest acceptation. 



FAMILY SCALAHIID.^. 



The Australian Tertiary species of this family belong to two 

 well-defined genera, Crossea and Scalaria. 



Crossea contains the turbinate species with an entire peristome, 

 the columella slightly produced and infolded to form a short canal, 

 the umbilicus more or less concealed or margined by a funicular 

 rib ; the genus has certain affinities conchologically with Ethaliay 

 and some species of Rissoina and Lacuna simulate it in their 

 apertural characters. 



Scalaria, used in its widest sense, contains the more or less 

 pyramidal species, without the canaliculate aperture ; it numbers 

 about 400 species, recent and fossil, and there is great need for 

 the dismemberment of the genus to facilitate specific reference. 

 The Eocene-species of France have been arranged by MM. De 

 Boury and Cossmann into several genera and numerous subgenera ; 

 and though the subdivision is perhaps rather strained, yet I have 

 largely availed myself of their classification in the elaboration of 

 our Tertiary species. I do not altogether appreciate the relative 

 values of their genera and subgenera ; and find it convenient to 

 admit only Scalaria as of generic value, though its species seem 

 to fall naturally into two chief groups — Scalaria (sensu stricto) 

 with an entire aperture and Acirsa with its incomplete peristome. 



Genus Crossea A. Adarns (1865). 



SYNOPSIS OF SPECIES. 



Outer lip plain; shell depressed turbinate; spire-whorls punctate. 



1. C. 2y'i^ince2JS. 

 Outer lip variced. 



Conic-turbinate, lirate. 2, C. suhlahiata. 



Globose-turbinate, smooth or obsoletely linear-sulcate at the 



base. 3. C. lauta, 



EXCLUDED SPECIES. 



Crossea parvula, Tenison- Woods, is transferred to Collonia. '"^n^ V 



The genus has hitherto been unknown in a fossil state, being 

 represented by six species, two inhabiting Japanese and four the 

 Australian seas. These species fall into three sections, to two of 

 which the fossil-species belong ; all are briefly indicated in the 

 following synopsis : — 



