DECAPOD CRUSTACEANS OF THE WEST INDIES 95 



Color in life. — Macrobrachium carcinus is the only species of 

 the genus on Dominica that exhibits longitudinal stripes on the 

 carapace and abdomen; whUe there is considerable variation in actual 

 color and in minor details of the color pattern, there is remarkable 

 uniformity in the major pattern. The dark colors vary from blue 

 black to brown; the lighter areas may be gray, pinkish tan, cream, 

 lavender, or various shades of yellow. One of the darker, almost 

 black-striped individuals is described below. 



Rostrum with longitudinal stripe of dark blue extending from 

 apex posterodorsally to broad transverse bluish-black band a short 

 distance posterior to posteriormost rostral tooth, and continuing 

 posteriorly to ridge bordering posterior margin of carapace; second 

 transverse band extending ventrally from longitudinal stripe at level 

 of base of fourth pereiopod; both bands ending ventrally in dorso- 

 lateral longitudinal black stripe, latter stripe extending posteriorly 

 from orbit to level of base of fifth pereiopod; areas between stripes 

 and bars yellow. Yellowish-tan longitudinal stripe present ventral to 

 dorsolateral dark stripe made bifid anteriorly by short narrow black 

 stripe extending posteriorly from orbit to level of anterior transverse 

 band. Fourth longitudinal blackish stripe ventral to yellowish-tan 

 one and extending from base of antenna to ridge on posterior margin of 

 carapace; latter stripe followed ventrally by yellowish-cream one, and 

 it, in turn, by broad grayish-blue marginal one; posterior ridge on 

 carapace cream to yellow. Abdomen with broad gray dorsomedian 

 longitudinal stripe extending from posterior half of first abdominal 

 somite to tip of telson; stripe, margined in black, broadest in third 

 abdominal somite and narrowing posteriorly; tannish-cream longi- 

 tudinal stripe flanking median dorsal stripe along almost entire 

 length; broad black stripe ventral to tannish-cream one and extending 

 along tergopleural junctions to telson, there fusing with dorsomedian 

 stripe; pleura mostly pinkish tan but with pale yellow spots, spots 

 becoming contiguous on fourth, fifth, and sixth pleura forming 

 narrow light yellow longitudinal stripe. Protopodite of uropod black 

 with lateral lunar-shaped yellow spot, outer ramus mostly black 

 with median yellow spot in proximal section, distal section black; 

 inner ramus with proximal three-fourths yellow to light brown and 

 with black distal fourth. 



Antennule with black markings on distal portions of segments 

 of peduncle and lateral area of proximal segment; undivided ramus 

 dark tan and divided one light tan. Antenna with black markings on 

 peduncular portion; antennal scale with black lateral border, yellowish 

 beige thickened lateral portion, and bright blue lamellar portion; 

 flagellum Ught tan. Third maxilliped mostly white with dark bands 

 at distal two articulations. First pereiopod lavender with cream 



