VERMIOLOGY. 



Scalaria, the type of which genus is Scalaria pretiosa, figured in a 

 former part of this work, a shell, valued in former days at a vast 

 price : at forty or fifty guineas, and, indeed we have seen a specimen, 

 only a few years ago, realize at the public hammer more than thirty 

 pounds. But the true Scalaria does not precisely agree with our 

 present shell, even generically considered : the chief distinction of 

 that highly appreciated object of curiosity consists in the body of 

 the shell forming throughout, from its mouth to the apex, a spiral 

 tube, like some of the Serpulae or worm-shell tribe, while in every 

 true turbinated shell, all the wreaths are in contact ; the anfractal 

 line of the whorl of the second wreath, resting upon and being united 

 with the first, and thus continuing to the tip or extreme point, 

 of the spire. In the true Wentletrap, the volutions of the tube 

 are distinctly unconnected, but it is at the same time traversed longi- 

 tudinally, from the mouth to the apex, by several lateral ridges or 

 plates, which touch the convexity of every volution in its progress 

 throughout, and thus serve to strengthen and sustain the shell 

 unbroken. Thus, it will appear, that destitute of those lateral 

 supports, the shell would be no other than a spiral tube, like the 

 Serpulae, and not a turbinated shell. From this form, so evident in 

 the true Scalaria, there are, however, transitions that approximate 

 with or blend into the turbinated shell, and thus, in some degree 

 unite the character of both ; those are the turbinated shells which 

 have the sutures of the whorls connected, at the same time that they 

 possess also the lateral longitudinal ridges or plates, although not 

 absolutely requisite for the support of the shell, as in the true 

 Scalaria?. The latter shells are the bastard or false Wentletraps 

 of English collectors, of which the Turbo Claihratus of our own 

 shores afford a very illustrative example, and which moreover assi- 



