26 MALACOZOA. CEPHALOPODA. SEPIINA. SEPIOL1. 



3. Ccecdlium TrachSa. Shell subcylindrical, arcuate, 

 glossy, annulated. Trachea, the windpipe. 



GENUS 10. DENTALINA. Shell subcylindrical, some- 

 what tapering, more or less arcuate, composed of nu- 

 merous oblique cells disposed in a single series ; aperture 

 submarginal. Dens, a tooth, or Dentalium, a tooth- 

 shell. D'Orbigny. 



1. Dentalina linedris. Shell subcylindrical, a little 

 compressed, slightly arcuate, glossy, smooth, posteriorly 

 longitudinally striato-sulcate, of about fourteen oblique 

 cells. Linedris, very slender. 



ORDER I. 

 CEPHALOPODA CRYPTAD1BRANCHIATA. 



Branchise laminated, concealed by the sac formed by 

 the closed mantle. Head surrounded with eight fleshy 

 appendages, by some called feet, by others arms, to 

 which, in certain genera, are added two long tentacula 

 or pedunculated arms. The body generally naked, some- 

 times partially enclosed in a shell. 



FAMILY I. SEPIINA. 



Animal with the body globose, oval, or oblong ; 

 the mantle united so as to form a sac ; an internal dorsal 

 horny or calcareous lamina ; eyes generally very lasge ; 

 head terminated by eight or ten fleshy appendages, fur- 

 nished with acetabula or suckers ; a sac, containing an 

 inky fluid, opening into the infundibulum. 



SECTION I. DECACERATA. 



With eight arms, and two tentacular appendages. 



GENUS 1. SEPIOLA. SEPIOLE. 



Head nearly as broad as the body, with eight ta- 

 pering fleshy arms, furnished with suckers on their inter- 

 nal surface, and two more elongated slender tentacula, 

 enlarged at the end; the first pair of arms shortest; 



