332 



LO WER IN VER TERRA TES. 



stem. Our two best-known species are Fxilgur carica and Scycoty2yus canaliculatus. 

 The former is a heavy shell with a short spire ornamented by a row of tubercles. The 

 latter is much more delicate, and is covered with a hairy epidermis, the sutures of the 

 spire being marked with a deep revolving channel. These shells are both inhabitants 

 of water of moderate depth, coming to the shore only for the purpose of oviposition. 

 Their egg-cases, which are very peculiar, are frequently cast on the shore and attract 

 the attention of the most casual observer. They consist of a series of flattened mem- 

 branous capsules attached \)y one edge to a cord, and having opposite the point of at- 

 tachment a more transparent spot, indicating the place where the young are subse- 

 quently to make their exit. When laying these long strings, the snail goes beneath 

 the surface and as the ribbon begins to be formed, it appears above the sand, slowly 



Fig. 414. — Pijrula decussata, pear-snail; a, dorsal, b, lower surface. 



increasing in length, until the whole of its two or three feet of extent are formed. 

 The first part of the cord is without capsules for about three inches, then come a few 

 cases imperfectly formed. Each capsule contains a number of eggs, and specimens 

 taken some time after oviposition show the shell formed, repeating in miniature the 

 essential features of the parent. 



The name Fulgur (lightning) was applied on account of the zigzag brown streaks 

 with which young specimens (and older ones in warmer waters) are marked. Fulgur 

 carica is used extensively by fishermen as bait. Another species, living further south, 

 is noticeable from the fact that it is reversed or sinistral, receiving on this account the 

 specific name perversa. 



With the genus Buccinum we take up a series of forms, whose position is less 

 doubtful than some of those just mentioned. Buccinum is a northern genus of shells 

 covered with a horny epidermis, having a large aperture, a siphonal notch rather than 



