102 U.S. NATIONAL MUSEUM BULLETIN 292 



Apparently members of this species are always hungry, and the 

 introduction of a small piece of meat or an earthworm into a pool 

 will set them into frantic motion — meeting one another they "flash" 

 their chelae, and usually one large male, obviously the dominant 

 member of the crenulatum population of the pool, will temporarily 

 drive the smaller shrimps and other members of its species away. 

 Should a small shrimp get to the food before the larger ones find it, 

 the small one grasps the morsel in its chelae and races for shallow 

 water; if, as it races away, other shrimps are encountered on the 

 bottom of the pool, it immediately rises above the animals it en- 

 counters and swims for cover. 



Distribution. — West Indies, Panama, and Venezuela (Jamaica, 

 Hispaniola, Saint Croix, Guadeloupe, Dominica, Grenada, Trinidad). 



Dominica Stations: 1-4, 7, 11-13, 17, 18, 22, 23, 28, 30, 32, 33, 36, 

 39, 42-46, 48, 49, 50, 52, 54-56, 59, 61, 63, 65, 66, 68, 74-76, 78-81, 

 84, 85, 87, 95, 96, 100, 105, 109 (0-1,350 ft.). 



Remarks. — In the absence of color after preservation, this species 

 is often difficult to distinguish from M. faustinum; this is especially 

 true of young specimens and even adults that have lost the major 

 second pereiopod. 



Females with eggs were collected in February, March, April, May, 

 August, and September. The absence of ovigerous specimens among 

 the 23 females taken in January and the fact that only 4 of 34 females 

 were carrying eggs in February, coupled with the evidence that 4 

 of the 5 females taken from April through September bore eggs, 

 suggest that M. crenulatum may have a prolonged breeding season, 

 beginning in February; the species was not collected in June, October, 

 November, and December. 



20. Macrobrachium faustinum (De Saussure) 

 Figures 23, 25d, j 



Palaemon spinimanus H. Milne Edwards, 1837 [part], p. 399 [type-locality: 



Antilles and Brazil; not Palaemon spinimanus Latreille, 1818]. 

 Palaemon Faustinus De Saussure, 1857c, p. 505 [type-locality: near Jacmel, 



Haiti]. 

 Palaemon (Macrobrachion) Faustinus — ^Von Martens, 1872, p. 137. 

 Bithynis spinimanus. — Pocock, 1889, p. 10. 

 Palaemon Olfersii. — Pocock, 1893, p. 408 [not Palaemon Olfersii Wiegmann, 



1836]. 

 Palaemon cubanus (Gudrin ms) Sharp, 1893, p. 124 [type-locality: Cuba]. 

 Bithynis faustinus. — Rathbun, 1897c, p. 45. 

 Bithynis olfersii. — Rathbun, 1901 [part], p. 124. 

 Macrobrachium faustinum. — Chace and Holthuis, 1948, p. 23. — Holthuis, 1952, 



p. 88, pi. 22; pi. 23a-c. 



Diagnosis. — Carapace with antennal and hepatic spines, without 

 branchiostegal spine. Rostrum reaching nearly or quite as far as 



