464 Ml-. J. Alder on JefFreysia and Chemnitzia. 



sub basi vibraculorum recondenda, involvenda; evoluta cer- 

 vicem latitudine vix cedens, longitudine pedem jequans 1. su- 

 perans, teres, versus apicem sensim attenuata, ore apicali minuto 

 (edentulo ?) . Mentum elevatuuij a solea discretum, facie superne 

 latiore, suifulcro angustiore solese adnatum, antrorsum declive, 

 soleje marginem anticum vix attingens, antice latius, rotundatum 

 1. bilobum, Isete vibrans." 



To remove, however, any further doubts upon the subject, we 

 shall let Professor Loven explain his own meaning, by giving a 

 translated extract from his paper in the Royal Swedish Academy's 



Proceedings: — 



" The animal" (of Odostomia) " likewise shows, as Lowe has 

 already remarked, the same characters" (as Chemnitzia), " which 

 however have not up to the present time been properly under- 

 stood. Lowe's description runs thus : ' Buccse labiales coalitse, 

 infra tentacula exsertse, proboscidem abbreviatam, depressam, 

 profunde emarginatam s. bilobam referentes,' and it has gene- 

 rally been supposed that this part answers to the muzzle of 

 Turbo : but that is not the case. This perfectly formed part is 

 what I would call the mentum, the muscular mass which is so 

 extremely developed in Natica, covering posteriorly a great part 



of the tentacles and mouth The proboscis, 



on the other hand, is again found in Odostomia 

 and Turbonilla [Chemnitzia) in its place, that is, 

 under the veil which is formed by the union of 

 the bases of the tentacles, and is a very long organ 

 for catching prey, which can only seldom, and by 

 persevering observation, be detected. This maybe 

 thereasonwhyithas been overlookedhereas well as 

 in Eulima,vf\ieYe it is also very long, but is seldom 

 extended in captivity." The more completely 

 to illustrate these remarks, a woodcut from a 

 tracing of M. Loven's figure has been added. 



My own observations on the living animals, 

 as far as they go (for I have not seen the pro- 

 boscis exserted), agree entirely with those of the 

 distinguished Swedish Professor. 



I have considered it necessary to go thus mi- 

 nutely into the characters of Chemnitzia, because 

 upon them undoubtedly tm-ns the question whe- 

 ther we shall admit Jeffreysia into the genus or 

 not ; and Mr. Clark, who has had most favour- 

 able opportunities of observation, and has writ- 

 ten much, and very decidedly, on the subject, 

 seems vet in the dark as to what the characters of the genus 

 really are. Your readers will, I think, agree with me m the 

 conclusion, that this long retractile proboscis, which a com- 



