LOLIGO PEALII (A Squid). 



Phylum XI, MOLLUSCA; class 4, CEPHALOPODA; sub-class i, 

 DIBRANCHIATA; order i, DECAPODA. 



HABITAT. The species of Cephalopod which forms the subject of 

 this study is common along our Atlantic coast, sometimes occurring in 

 schools. Its rapid movements, its changing play of colors, and its 

 large staring eyes make it an object of more than ordinary interest, even 

 to the causual observer of shore life. Other species and other genera 

 are distributed in seas the world over. They live on small fishes, 

 crustaceans, and the like, and in turn form the food of larger animals of 

 the same groups they themselves feed upon. They are very generally 

 used for bait by the fishermen of some coasts. In a few localities they 

 are used also for food by human beings. 



Technical Note. As squids are readily taken in trawl nets or fish pounds, 

 a supply for laboratory purposes can be secured from some marine 

 distributing station. When preserved material is to be used male 

 specimens having the vascular system injected are much to be pre- 

 ferred because of the facility with -which details can be made out. For 

 complete dissection, however, it is best to have on hand specimens that 

 have not been injected so that the more expensive material need not be 

 torn to pieces, but may be kept for succeeding classes. As a preserva- 

 tive solution formaldehyde should be used in all cases in preference to 

 alcohol. Of course if the student lives near the sea shore fresh or 

 living specimens should be secured. 



EXTERNAL FEATURES. Having thoroughly soaked or washed the 

 formaldehyde from a preserved squid, place it in a pan of water and 

 note the following: 



a) The cylindrical body tapering somewhat toward one end. Scat- 

 tered over its surface are a great many pigment spots, or chroma- 

 tophores. During life the size and shape of these spots, by 



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