GEOGRAPHIC DISTRIBUTION. 



XV 



Table showing number of species included in the principal mono- 

 graphic works on Scaphopoda. 



Note. The number of Dew species in each work is, of course, 

 taken at the author's estimate. It is really less in most cases, part 

 proving to be synonyms. 



The genera are practically universal in distribution ; but the sub- 

 genera Fissidentalium, Heteroschisma, Bathoxiplms, Rhabdus, Epi- 

 siphon and Compressidens are almost exclusively deep water forms. 

 Typical Dentalium, Antalis and Graptacme are mainly shore groups. 

 The subgenera are more or less localized, though not nearly to the 

 same extent as groups of like rank in the Gastropoda or Polypla- 

 cophora. 



The bathymetric range of Scaphopods is considerable, but as data 

 thereon are abundantly given in the text, no examples need be cited 



here. 



Eastern Atlantic and Mediterranean. 



Species marked with an asterisk in the list following occur also 

 in the Western Atlantic or Gulf of Mexico. With the exception of 

 D. entails, which is a shore form having the northern distribution 



