46 CRUSTACEA OF ALABAMA. 



parts of the Gulf coast. The characters by which it may be recognized may be gathered 

 from the figures. It is generally an inch or an inch and one half long and differs in no 

 respect from typical Atlantic coast specimens with which compared. Compare the fol- 

 lowing~species. 



Palaemonetes paludosa, Kingsky. 



(= P. exilipes, Stimpson.) 

 (Plate V, Fig. 5.) 



This species was found near Tuscaloosa in great abundance and has been noticed 

 as far south as Florida. 



From P. vulgaris it may be distinguished by the elongated last abdominal segment, 

 the short appendage of the antennulary flagella and the straight rostrum with seven or 

 eight teeth above and two smaller ones below near the apex. The scale (scaphocerite) 

 of the antennule is short and the first foot has a very short, bristly hand. The telson is 

 spiny toward the tip. 



FAMILY PEN /FAD JE. 



The family is represented in America by two species of the genus Penaeus, which 

 in external characters approaches Palaemonetes. 



GENUS PEN.EUS. 

 Penaeus setiferus, M - Edwards. 



(Plate V, Fig. 6.) 



The common prawn of the fishermen is very abundant along the Gulf coast and its 

 capture and sale for food forms a considerable business. The half-grown young are 

 termed "shrimp" by dealers. The prawn is marketable from February to May, when 

 it is likely it retires to shallow estuaries to spawn, the young or shrimp are ready for 

 market by June, and are greatly prized. 



The following description combines generic and specific characters and may be 

 taken as a description of a female specimen of average size : 



Entire length 14.5 cm., spine projecting beyond head 22 mm., length of thorax and 

 spine 52 mm., lamella of antenna 23 mm., flagellum about 30 cm. or over twice the length of 

 the whole body; longest leg 57 mm. or rather longer than thorax and spine; telson 2 cm., exo- 

 podite of tail-fin 24 mm., height of last abdominal segment 14 mm. The frontal spine is 

 long and but slightly curved, its slightly expanded superior blade with about nine acute 

 teeth, below with two teeth. The basal segment of the antennules is excavated for 

 the reception of the eye and the peduncle of the latter and the excavation is guarded 

 within by a curved lamellate "scaphocerite," the two succeeding joints are much smaller, 



