88 SHELLS AND SHELL-FISH. PART I. 



there is abundant evidence, even if these species are 

 omitted, that the PyruUnce form a circular group, in 

 which scarcely a link is wanting. This will be more 

 evident upon arranging the whole of the genera in a 

 tabular form, and placing the few species we have 

 already named in the natural series of their succes- 

 sion. 



Genera of the Pyrulinje. 



List of the Species, sJiowing the progressive Change of one Genus to the 



other. 



"tuba. Ency. Meth. pi. 426. fig. 2, 

 perversa. lb. fig. 4. 



candelabrum. lb. pi. 437. fig. 3. ; pi. 438, fig. 3. 

 Pyrula <| carina. lb. pi. 433. fig. 3. 



canaliculata. lb. pi. 436. fig. 3. 

 spirata. lb. pi. 433. fig. 2. 

 _Burdigalensis. Sowerby's Genera, fig. 2. 



rtricarinata. lb. fig. 3. 

 T?,r„T A 3 fi«^"s- Ency. Meth. pi. 432. fig. 1. 



ricuLA ■) reticulata ia?«. lb. pi. 432. fig. 2. 



tcaudata lb. pi. 436. 



Rapella 



Tpapyracea. lb. pi. 436. fig. 1. 



3 abbreviata. lb. pi. 426. fig. 2. 



ieffusa Sw. lb. pi. 434. fig. 1. {Pyrula Rapa.) 



C nerito'ides. lb. pi. 435. fig. 2. 



Smelongina. lb. pi. 435. fig. 3. a. — d. 

 lineata. lb. pi. 432. fig. 5. 

 coronata Siv. lb. pi. 432. fig. 3. a, b. 

 hippocastanum. lb. pi. 432. fig. 4. 



CuMA sulcata Siv. — followed by Pyrula tuba. Sec. 



(75.) The strong resemblance of the Pyrulince to 

 the PurpurincB is a constant subject of remark among 

 conchological writers, and is so strong as to be often 

 exceedingly perplexing. We now allude only to the 

 latter group, as left by Lamarck ; but many of these are 

 so like our genus Myristica, that it is only upon close 

 inspection their distinguishing characters are detected. 

 Now, this strong resemblance can be accounted for in 

 two ways : first, by supposing that the two groups re- 

 present each other generally in their own respective 

 circles ; and secondly, that this strong analogy actually 

 extends to the particular genera of each sub-family. 



