DENTALIUM, 



TUBUS testaceiis, regularis, leviter arcuatus; 

 versus extremitatem posticam sensim attenua- 

 tus, interdum fissura superius et appendiculis 

 duobus utroque latere postice instructus; utra- 

 que extremitate pervius. 



We are aware that we sliall incur the displeasure of some 

 of our rigidly scientific friends, hy introducing the Genus 

 Dentalium in our work on the Genera of Shells, for the 

 same reason as some complaints have already been insti- 

 tuted against us for admitting the Galeolaria, that is, 

 because the animal which inhabits it does not belong to 

 the same class as the greater number of testacea; but 

 assured as we are that a right knowledge, and con- 

 sequently "a natural classification of shells, will never be 

 attained but by the study of the animals, we still think 

 ourselves justified in presenting such genera to our read- 

 ers, because, whatever may be the nature of their animals, 

 we are engaged to give an account of the shells alone, 

 and the Dentalia are as decidedly shells as any others. 

 We may further add, that so little is known at present 

 upon the subject, that it is not without evident doubt 

 that Lamarck has placed it among his Atinelides, 



The Dentalia are regular, slightly arched, generally 

 smooth, sometimes longitudinally grooved or striated, 

 and sometimes transversely and annularly striated, shelly 

 tubes, open at both extremities and sensibly smaller at 

 the posterior. Many of the species appear to be entire 

 at the smaller end, but we have not unfrequently observed 

 in others a more or less elongated longitudinal fissure, 

 commencing at the upper part of this posterior aperture, 



