October. Larval development of the 2 species is 

 similar, and 10 zoeal stages and a postlarval 

 stage were described for both. The chief differ- 

 ence between larvae of the two species is in the 

 presence of a pair of chromatophores found on 

 the second abdominal sternite of P. pugio but 

 lacking in P. vulgaris. The number of larval 

 stages and length of the developmental period 

 may vary, and such variation is apparently due to 

 availability of suitable food. In rearing Palae- 

 m<metes with artificial diets, Broad (1957b) 

 found that algae alone were not sufficient to pro- 

 mote survival ; mixtures of plant and animal food 

 were better, but best survival was obtained by 

 feeding living Artemia nauplii. Frequency of 

 molting and rate of development were directly 

 correlated with amount of suitable food available. 



Responses of the white chromatophores of 

 P. pugio to light and temperature have been in- 

 vestigated by Fingerman and Tinkle (1956). The 

 tendency of white pigment to disperse in bright 

 light, especially on a white background, is nor- 

 mally antagonized by a tendency of the pigment 

 to concentrate with increased temperature. This 

 mechanism is interpreted as maintaining a steady 

 state of white chromatophores in nature. 



Pearse (1952b) reported Probopyrus pandicola 

 (Parkard) from the gill chamber of this species 

 in Texas. 



Family Gnathophyllidae 



Caridea with first two pairs of legs chelate, 

 first pair smaller than second; carpus of second 

 pair not subdivided. Rostrum short and toothed. 

 Third article of third maxillipeds very broad. 

 Mandibles simple. Second maxillipeds with short 

 seventh article. The family contains but a 

 single genus (Hay and Shore, 1918). 



Genus Gnat hophy Hum Latreille, 1819 



Armstrong, 1940, p. 6 (rev.).— Hemming, 1958b, p. 156. 



Gnathophyllum modestum Hay 



Figure 50 



Gnathophyllum modestum Hay, 1917, p. "2. — Hay anil Shore. 

 1918, p. 395, pi. 28, fig. 1— Manning, 1963; p. 48, figs. 1-2. 



Recognition characters. — Body short and thick ; 

 carapace with a moderate carina continuous in 

 front with rostrum and extending about two- 

 thirds of distance to posterior margin. Rostrum 





r ^ T "7-- tiS-'J.'MT 



'.."P 



5*- ''' . 



Figure 50. — Gnathophyllum modestum Hay. A, anterior 

 portion of carapace, lateral view ; B, antennular pe- 

 duncle, ventral view ; C, telson and left uropod ; D, an- 

 tennal scale; 1 mm. indicated, B and D to same scale 

 ( after Manning, 1963 ) . 



obliquely truncate dorsally and armed with five 

 or six dorsal teeth ; one or two small ventral teeth 

 near tip; tip reaching to distal end of basal article 

 of antennule. Suborbital angle prominent; anten- 

 nal spine present; anterolateral angle strongly 

 produced. Eyes rather large and with a promi- 

 nent, conical, black protuberance on cornea. 

 Antennular peduncles with basal article large, 

 stylocerite reaching beyond middle of article, a 

 spine at anterolateral corner of article; second 

 article with a similar but smaller and blunter 

 anterolateral spine; second and third articles of 

 about equal length; outer antennular flagellum 

 bifurcate, upper ramus longer and thinner than 

 lower ramus. Antennal scale reaching beyond 

 antennular peduncles, lateral margin almost 



MARINE DECAPOD CRUSTACEANS OF THE CAROLINAS 



61 



