Color. — Often nearly colorless and transparent; 

 sometimes with body pale yellow, yellowish green, 

 greenish brown, brown, red, black, black with 

 white spots and bars; bright blue patches on 

 dorsal and lateral surfaces; often mottled, striped, 

 or barred, and corresponding in pattern to irregu- 

 larly colored bits of weed (various authors). 



Habitat. — Common in floating masses of Sar- 

 gassum; surface waters. 



Type locality. — Floating gulfweed. 



Knoivn range. — Newfoundland to Puerto Rico, 

 through Gulf of Mexico to Texas; Bermuda; near 

 the Azores and Cape Verde Islands; Cape of 

 Good Hope (?) (Holthuis, 1951b; Sivertsen and 

 Holthuis, 1956). 



Remarks. — Ovigerous females have been ob- 

 served in inshore waters of the Carolinas and ad- 

 jacent western Atlantic region from July to 

 October. They have been observed in the Gulf 

 of Mexico from April to June. In the middle and 

 western Atlantic they have been observed in June 

 (Sivertsen and Holthuis, 1956). Gurney (1936a) 

 described the first stage larva. 



Pearse (1952b) reported the parasitic Pro- 

 bopyrus latreuticola (Gissler) in the gill cavity 

 of this shrimp near Port Aransas, Texas. 



Brown (1939) found four kinds of pigment in 

 this shrimp (white, red, yellow, and blue) similar 

 to pigments .found in Hippolyte, Leander, and 

 Palaemonetes species. The red and yellow pig- 

 ments respond to white background by concentra- 

 tion into the chromatophore centers and to black 

 background by dispersion into the chromatophore 

 branches. Latreutes has a great abundance of 

 white pigment which may vary in color from 

 yellowish white to clear white. Darkness pro- 

 duces concentration, and darkness or black back- 

 ground with low intensity of incident light calls 

 forth concentration of the reflecting white 

 chromatophores. Direct sunlight of a bright sky 

 produces dispersion of white pigment in spite 

 of black background. Blue patches on the animals 

 apparently consist of blue pigment accumulated in 

 particular white chromatophores. Brown con- 

 cluded that the different color patterns in this 

 species are not solely results of responses to 

 particular situations, but are at least partly 

 genetic patterns repressed or encouraged by light 

 intensity in color of the background. The re- 



sponse is similar to responses in crustaceans hav- 

 ing far less ability to change color. 



Latreutes parvulus (Stimpson) 



Figure 64 



Rhynchocyclus parvulus Stimpson, 1866, p. 48. — 1871b, p. 124. 



Concordia gibberosus: Hay and Shore, 1918, p. 391, pi. 26, 

 fig. 11. 



Latreutes parvulus: Holthuis, 1947, p. 59. — 1951b, p. 131, fig. 

 28 (rev.). 



Recognition characters. — Rostrum laterally 

 compressed, almost circular in outline in female, 

 more elongate in male; upper margin with six to 

 eight teeth in female, two to four in male; a few 

 small teeth on tip; lower margin unarmed or 

 with up to five shallow teeth; ventral part of 

 rostrum produced somewhat backward. Carapace 



Figure 64. — Latreutes parvulus (Stimpson). A, ovig- 

 erous female in lateral view, X 6; B, carapace of 

 ovigerous female in lateral view, X 6; C, carapace 

 of male in lateral view, X 6; D, antennule, X 13; E, 

 antennal scale, X 13; P, first leg, X 17; G, second 

 leg, X 17; H, third leg, X 17; I, telson and right 

 uropod iu dorsal view, X 17 (after Holthuis, 1951b). 



MARINE DECAPOD CRUSTACEANS OF THE CAROLINAS 



79 



