raal division of telson with rather strong spines; 

 distal division with weak spines and cilia in longi- 

 tudinal lines. Uropods hard proximally, mem- 

 branous distally; basal article bispinose, a row of 

 denticles along margin of hard part, and lines of 

 minute spines and setae on upper surface of mem- 

 branous part. 



Measurements. — Length of body from orbit to 

 tip of telson: to approximately 450 mm. (18 

 inches), occasionally larger. 



Variations. — Aside from individual variations 

 which will not be discussed here, the species ex- 

 hibits marked allometric variations with age as 

 well as sexual dimorphism. These features were 

 discussed in detail by Crawford and deSmidt 

 (1922) and are summarized here. Antennae of the 

 young are longer in proportion to the body than 

 in adults. Setae present on the young disappear in 

 the adult and the sharpness of spines on the body 

 tends to diminish with age, except for those on 

 anterior portions of the carapace. 



As pointed out in the description, only the fe- 

 males have chelate fifth legs. In adult males, the 

 second pair of legs is extraordinarily developed. 

 They are long, rarely used in walking, and the 

 dactyl is long, curved, and provided with a brush 

 of setae. The length of the dactyl, its curvature 

 and set at ion increase with age. Sexual differ- 

 ences in the pleopods are given in the description. 



Males have a relatively more inflated and 

 longer carapace than females. Conversely, in fe- 

 males the abdomen represents a greater propor- 

 tion of total length of the body than in males. 

 Maximum lengths of the two sexes, however, are 

 about the same (Creaser, 1952). The posterior 

 margin of the sternum in males is narrower than 

 the comparable structure in females and the ster- 

 num is longer. 



Color. — Coloration largely separable into two 

 groups, (1) lightly colored individuals ranging 

 from light gray and tan to shades of green and 

 light brown, and (2) darkly colored individuals 

 varying from shades of red to deep brown and 

 blue. Abdomen spotted witli yellowish ocelli; 

 posterior margin of each segment edged with yel- 

 low or orange, lower angles of segments marked 

 with bluish or greenish tints and sometimes addi- 

 t ional colors. Tail fan crossed by bands of orange, 

 yellow, and black, fringed with white. Pleopods 

 usually orange, about half of surface covered by 



a black blotch. Legs striped longitudinally with 

 blue. Ventral surfaces of body light yellow ; tho- 

 racic sternum marked with irregular radiating 

 stripes. 



Young with coloration of carapace arranged in 

 transverse bands, usually three, middle one dark; 

 antennae frequently ringed with alternate light 

 and dark bands; legs ringed with blue (Crawford 

 and deSmidt, 1922). 



Habitat. — On reefs or among rocks, among 

 growths of sponges or other objects which afford 

 protection or places of concealment; low-tide 

 mark to depths of about 50 fathoms. Experimen- 

 tally, lobsters at Bermuda have withstood depths 

 of 250 fathoms (Creaser and Travis, 1950). 



Type locality. — Erroneously given as East In- 

 dies ("des Grandes-Indies"). 



Known range. — North Carolina through Gulf 

 of Mexico and West Indies to Rio de Janeiro, 

 Brazil; Bermuda. 



Remarks. — A number of papers have been pub- 

 lished concerning the general ecology of Panu- 

 lirus argus. Only a summary of this work can be 

 given here. The most comprehensive single, gen- 

 eral treatment is that of Crawford and deSmidt 

 (1922) for the species in Florida, but substantial 

 additions to this work have been given by Dawson 

 (1949, 1954), Dawson and Idyll (1951), Lewis 

 (1951), Lewis, Moore, and Babis (1952), Mar- 

 shal] (1948), and Smith (1951). Mattox (1952) 

 gave biological notes on the species in Puerto 

 Rico, and Creaser (1950, 1952), Creaser and 

 Travis (1950), and Sutcliffe (1952, 1953, 1957) 

 discussed the species in Bermuda. 



North Carolina must be regarded as the ex- 

 treme northern edge of the range o'f this species, 

 and, indeed, concentrations of the species large 

 enough to be exploited commercially occur only 

 in southern Florida, the West Indies southeast to 

 Puerto Rico, and at Bermuda. A large population 

 may exist in deep water in the northern Gulf of 

 Mexico (Moore, 1962). Differences in growth rate 

 and breeding habits may exist among these areas. 



PanuliruA argus grows to a large size. In its 

 first year of life it reaches a length of about 2 

 inches (measurements of this species usually 

 given in inches in U.S.A.) and, though growth in 

 the young individuals is more rapid than in older 

 animals, increments in length after that time are 



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