Wp: MANUAL OF THE MOLLUSCA. 
OMMASTREPHES, D’Orbigny. Sagittated calamary. 
Etymology, omma, the eyes, and strepho, to turn. 
Synonym, Hyaloteuthis (Gray). 
Type, O. sagittatus, Lam. 
Body cylindrical; terminal fins large and rhombic. Arms 
with two rows of suckers, and sometimes an internal mem- 
branous fringe. Tentacles short and strong, with four rows of 
cups. 
Pen consisting of a shaft with three diverging ribs, and a 
hollow conical appendix. Length from one inch to nearly four 
feet. 
The sagittated calamaries are gregarious, and frequent the 
open sea in all climates. They are extensively used in the cod- 
fishery off Newfoundland, and are the principal food of the 
dolphins and cachalots, as well as of the albatross and larger 
petrels. The sailors call them ‘‘ sea-arrows,”’ or ‘‘ flying squids,” 
from their habit of leaping out of the water, often to such a 
height as to fall on the decks of vessels. They leave their eggs 
in long clusters floating at the surface. 
Distribution, 14 recent species; similar pens (4 species) have 
been found fossil in the Oxford clay, Solenhofen ; it may, how- 
ever, be doubted whether they are generically identical. There 
is 1 tertiary species. 
THYSANOTEUTHIS, Troschel. 1857. 
Litymology, thysanos, a fringe. 
Arms sessile and webbed, but without hooks. Tentacles fur- 
nished with cups. in long. Pen sagittate. Two recent 
species, 7’. rhombus, T’. elegans. Mediterranean. — 
Louiouvs, Stp. 1856. 
Pen horny, broad, with the shaft sharp-keeled; no muscular 
bands tn the funnel; suckers with a raised band. Left fourth 
arm hectocotylised. 
Distribution, 2 species. Indian Ocean. 
PLESIOTEUTHIS, Wagner. 1860. 
Pen slender, with a central and two side ridges. Point 
arrow-shaped. Arms with hooks. 
Distribution, 2 species, Lias. Solenhofen slate. 
