162 LECTURES ON MOLLUSCA. 



found fossil in the German Jurassic strata, with the traces of the cut- 

 tle itself, prove that the Spiny calamaries were equally the tyrants of 

 the ancient seas. The Sea-arroios live in large groups in the open 

 sea. They are themselves the prey of whales and birds. In order to 

 avoid the attacks of their pursuers, they dart out of the water like the 

 flying fish, often to such a height that they fall down on the decks of 

 vessels. The eyes of these creatures have a deep lachrymal groove at 

 the upper edge, and the ears are furnished with a longitudinal crest. 



Family Teuthidte. (Squids.) 



In the Squids the eyes are without lids, and covered with the skin, 

 as in Cranclua; but the mantle is strengthened with internal cartil- 

 ages, as in the Sea-arrows. The genera are Gonatus, Loligo, Teutliis, 

 Sepioteuthis , Bossia, Sepiola, and Fidenas; with the fossil remains of 

 Leptoteutliis , Tcudopsis, Beloteuiliis, and Geoteuthis. 



The Squids form an important element in the North Atlantic fish- 

 eries. The common Loligo is the favorite food of the Cod, and is 

 therefore itself fished for bait. One half of all the cod taken on the 

 banks of Newfoundland are said to be caught by it. "When the vast 

 shoals of this mollusk approach the coast, hundreds of vessels are 

 ready to capture them, forming an extensive cuttle fishery, engaging 

 five hundred sail of French, English, and American ships. During 

 violent gales of wind, hundreds of tons of them are often thrown up 

 together in beds on the flat beaches, the decay of which spreads an 

 intolerable effluvium around." They must themselves be consumed 

 in enormous numbers; for it has been estimated that a single squid 

 will lay in one season forty thousand eggs. The pens of the squid 

 tribe are loose supports in a pouch along the back. In old individuals, 

 sometimes two or three are found laid together. They are analogous 

 to the "bones" or steel plates in ladies' stays — an instrument which 

 ought not to be needed by a vertebrated animal. 



The Sejyiolas are pretty little creatures, with round purse-like 

 bodies, and a wing-like fin on each side. They live near shore, and 

 may often be seen darting about in rocky pools. They are considered 

 a delicacy in the South of France, where they are called supieta. 



The squids first make their appearance in the world's history during 

 the epoch of the Lias and Oxford Clay. The octopods may, indeed, 

 have existed, but their bodies have no hard parts that would be likely 

 to leave traces on the ancient rocks. Of the squids, not only the 

 horny pens and claws have been preserved, but even the muscular 

 mantle, the bottoms of the arms, and the ink bag filled with sepia 

 which an artist might envy. They must have died a very peaceful 

 death, as they always spill their ink under the slightest provocation. 

 Some of the ink bags of the Lias are nearly a foot long, with a brilliant 

 pearly coat. They probably formed part of the food of the formida- 

 ble Ichthyosaurians of that epoch. 



Family Sepiad^e. {True Cuttles.) 



The Cuttle-fish proper are furnished with a "bone," which consists, 

 on the back, of a hard, shelly dish, covered with membrane and end- 



