Fam. 73.] NATURAL HISTORY SOCIETY. 151 



1. Spirula, Lam. 



Animal with an internal calcareous, spiral shell ; the whorls 

 are in the same plane and free from each other, like a watch 

 spring ; the shell is divided into many chambers by partitions. 



The shells oi Spirula per onii, Lam, (Figs. 56 and 57), a pelagic 

 species, are occasionally thrown on the shores of Nantucket dur- 

 ing a storm, and probably at other places southward. The shell 

 is white, pearly and coiled in 2-3 turns. 



Family 72, OMMATOSTREPHID/E. 

 Characters mainly of the genus : — 



1. Ommatostrephes, D'Orb. 

 Body long, cylindrical ; arms short, with two rows of suckers ; 

 tentacles short, not retractile, the clubs with four rows of suck- 

 ers ; siphons valved, united by bands to the head ; shell horny, 

 small, slender, like a lance, wdth a hollow end cone. Abund- 

 ant in the open sea and extensively used as bait for cod fish. 

 Commonl}^ called " sea arrows " or " flying squids." 



1. Ommatostrephes iUecebrosa, Lesueur. Head large; body 

 elongate, cylindrial, fleshy, smooth ; tentacles short, like the 

 other 8 arms, and provided with 8 rows of numerous small 

 cups; fins rhombic, about J as long as the body, sides quite 

 pointed ; gladius narrow, ending in a large cone. Whole coast ; 

 frequently found near shore. 



2. Ommatostrephes Bartramii, Lesueur, (Figs. 58, 59). Head 

 short ; back with a longitudinal, violet band ; tentacles short, 

 with two rows of small cups at the end ; second and third pairs 

 of sessile arms with fins on the inner edge of the ventral side ; 

 gladius long, slender, with a small cone. Whole coast. 



Family 73, ONYCHOTEUTHID£. 

 The principal peculiarity of this family is the development of 

 hooks upon the arms in the place of more or less of the sucking 

 disks. 



1. Onychoteuthis, Lichtenstein. 



Arms with two rows of suckers, the rings of which are not 

 toothed ; tentacles thick, their clubs with two rows of strong 

 hooks, and at the base a rounded group of suckers ; gladius 

 lancet-form with an end cone. 



1. Onychoteuthis Banksii, Leach. (Figs. 60, 61). Head with 



