GASTROPODA. 905 
Conradella.] 
Cyrtolites having fine thread-like lines arranged in a reticulate manner, while in 
Conradella the surface is covered by strongly imbricating transverse lamelle, the 
raised edges of which are serrated. 
It seems to us that Conradella is in reality nearer Bucania than Cyrtolites. A 
careful comparison brings out what we conceive to be important agreements. Thus, 
in Bucania there is a rather long apertural slit, a large umbilicus and the whorls 
increase somewhat slowly in size, while the surface sculpture, though differing in 
detail, is of the same type. Of course, we do not wish to be understood to say that 
Bucania and Conradella are closely related, nor that there is any difficulty in keeping 
the two genera separate, the strong dorsal keel, less depressed and more slowly 
enlarging volutions, and the directness of the transverse imbrications in the latter 
being very obvious peculiarities. Yet, when we consider the general sameness of 
the types, we cannot escape the conviction that they were derived from the same 
stock. The great development of the lamelle, each of which must at first have been 
abrupt apertural expansions, is corroborative evidence for this view, since it is a 
feature recurring in even greater development in Tremanotus, a genus that doubtless 
was derived from Salpingostoma and Bucania. 
In the new genus Cyrtolitina (see pages 847, 856), the surface markings are some- 
what similar, but the lines of growth sweep backward on nearing the dorsum, causing 
a sinus in the outer lip, the apertural slit is much shorter, and the volutions fewer in 
number and much more rapidly enlarging. The long slit and the general form of 
the shell of Conradella remind one greatly of the Devonian and Carboniferous genus 
Porcellia, Leveille, yet it is more than doubtful if there is any true relationship 
between them. In Porcellia the surface markings are of a different type, while the 
innermost volutions are unsymmetrically coiled, showing that it was derived from 
a pleurotomarid rather than a bellerophontid stock, the symmetric coiling of the 
later whorls probably indicating partial atavism. 
Respecting the name of this genus, we would have been glad to restore Conrad’s 
Phragmolites (partitioned stone) were it not objectionable because it gives an 
incorrect idea of the fossil. Conrad believed his P. compressus to be a chambered 
shell. This, however, was soon learned to be an error, and as Hall placed the 
species unreservedly into Cyrtolites, which was proposed by Conrad at the same 
time, all subsequent paleontologists have followed in ranking Phragmolites as a 
synonym under Cyrtolites. Had the name ever attained currency, we would feel 
ourselves bound to revive it, on the score of priority, despite its inappropriateness, 
but as no one, so far as we can learn, ever adopted it, we thought it best to view the 
name as one that has failed of being established because of incorrect and insufficient 
definition. Yet we think it but justice to Mr. Conrad, who was a better paleontolo- 
