226 SYNOPTIC COLLECTION. 



The shell is notched and the animal has a short siphon. 

 According to Adanson l many living Cymbia were found 

 with living young in their bodies, thus proving them to 

 be viviparous. The young (there are only four or five in 

 each Cymbium) leave the mother when the shell is an 

 inch long. 



Strombus costatus Gmel. is a plain spiral in which the 

 whorls can be readily counted. The aperture of the 

 adult extends upward on the preceding whorl and be- 

 comes flaring with a recurved canal. No. 484 is an 

 antero-posterior section through the middle of the shell, 

 showing the internal structure, and No. 485 is a cross 

 section of another species, S. gigas. 



Pteroceras lambis Linn, carries this mode of develop- 

 ment farther than Strombus. It is illustrated by a fine 

 series (No. 486) showing marked changes between the 

 young and adult stages: (a) is a plain spiral having a 

 long, narrow, notched aperture with a thin, sharp, unorna- 

 mented margin ; (b) is the dorsal side, showing yellowish 

 color banded with red ; (c-f) all exhibit the plainness of 

 slightly older shells. In (g) the margin of the aperture 

 extends toward the apex as in Strombus, and in (h) and 

 (i) it goes beyond it, changing essentially the shape of 

 the shell and giving a wide, flaring aperture with a canal 

 at either end. The margin becomes fluted at first and 

 afterward extends outward in long, half open canals 

 which finally become closed solid spines 2 (see j and k). 



Phalium inflata Shaw (No. 487), has the first whorls 

 light colored and plain ; those succeeding may have the 

 marks of the lip or not, one being without them and two 

 having them. The canal is short and instead of being 

 prolonged as in Murex, it is sharply recurved. 



No. 488 is a section of a small specimen of Cassis 

 cameo Stimp. Cassis grows to a large size and is much 

 used in making cameos. 



1 See Adams, Genera of Moll., I, 1858, p. 158. 



2 Adams, loc. cit., I, p. 260. 



