130 NEW YORK STATE MUSEUM 



Suborder a 



Decapoda in which the cephalothorax is usually longer than 

 broad and the abdomen is large and well developed and carried 

 straight out behind. The second pair of antennae are long and 

 many jointed and the last pair of maxillipeds are leglike. The 

 walking legs are well developed and have the terminal joints of one 

 or more of them modified into chelae. The abdominal appendages 

 are generally all present, and the last pair, the uropoda, are broader 

 and form, with the terminal segment, a tail fin. 



The eggs are carried attached to the abdominal appendages of the 

 female, and the young are hatched in a free-swimming form quite 

 unlike the adult. This varies, however, greatly in different forms, 

 and in the crayfishes the newly hatched young are very like the adult 

 in everything except size. 



This suborder includes the shrimps and prawns, which are found, 

 sometimes in great numbers, among the seaweeds on piles or 

 wharves. The lobster, which is now extinct in New York city, 

 belongs in this group, as does the crayfish, common in the brooks. 



Keys to the macrurous Crustacea of North America are to be 

 found in the American Naturalist, 1899, v.33, as follows: "The 

 Caridea," J. S. Kingsley, p. 709 ; " Astacoid and Thalassinoid 

 Crustacea," J. S. Kingsley, p.SiQ; "The Astacidea," W. P. Hay, 



P-957- 



The Macrura are divided into four tribes : i Caridea, 2 Astacidea, 

 3 Thalassinidea, 4 Anomura. 



i CARIDEA 



Small or moderate sized forms with a rather compressed body. 

 Carapace smooth and without sutures and produced into a longer 

 or shorter rostrum, frequently toothed. The carapace is not fused 

 in front with the epistome (the frontal region between the eyes). 

 Antennae with a large scale. The thoracic legs are generally long 

 and delicate, one or more of the anterior ones being chelate. 



This group includes the shrimps and prawns, and our common 

 species represent the three families Crangonidae, Palaemonidae and 

 Penaeidae. 



