382 



BULLETIN OF THE BUREAU OF FISHERIES. 



Tribe CARIDEA. 



Natantia having the third pair of legs not chelate, the pleura of the first abdominal 

 segment overlapped by those of the second segment, the abdomen usually with a sharp 

 bend and the giUs always developed as phyllobranchiae. 



This large and important tribe comprises 153 genera, divided among 20 families. 

 Of the latter, 5 are represented in the Beaufort fauna. 



Family CRANGONIDAE ( = ALPHEIDAE of most authors) . The snapping shrimps. 



Caridea having the first two pairs of legs chelate, the first pair usually much stronger 

 than the others and often unsymmetrical, the carpus of the second pair of legs subdi- 

 vided, the eyes small and usually covered by the carapace, the mandibles deeply cleft 

 and the second maxillipeds with a very short seventh article. 



Of the 27 recognized genera the following are represented in the Beaufort region: 



KEY TO THE GENERA OP THE BEAUFORT REGION. 



a. Eyestalks covered by the carapace. 



6. Hand of large cheliped cylindrical; trunk legs with exopodites Synalpheus. 



bb. Hand of large cheliped compressed; trunk legs without exopodites Crangon. 



aa. Eyestalks completely exposed Automate. 



Genus SYNALPHEUS. Bate. CoutiSre. 



Synalpkeus Bate, 1888, p. 572: Coutiferc, 1899, p. 334. 



KEV TO THE SPECIES OF THE BEAUFORT REGION. 



a. Rostrum comparatively broad, not longer than the 

 supra-orbital lobes minus. 



aa. Rostrum comparatively slender, more or less ex- 

 ceeding the supra-orbital lobes. 

 b. Movable finger of small cheliped with a conspicu- 

 ous bunch of curled hairs. Rostrum little 

 longer than supra-orbital lobes . . . longicarpus. 

 bb. Movable finger of small cheliped without a bunch 

 of ciurled hairs. Rostrum considerably longer 

 than supra-orbital lobes townsendi. 



Synalpheus minus (Say). PI. xxvi, fig. 3. 



Alphcus minus Say. 181S, p. 245. 

 Synalpheus minus Couti^re, 1909. 



Similar in appearance to the two following species 

 but with a much shorter and broader rostrum which 

 has at the base about the same width as the supra- 

 orbital spines and hardly exceeds them in length. 

 The sides of the telson are not strongly convergent and 

 the spines at its tip are about equal in length. The 

 spine on the basal article of the antennule reaches to near the middle of the second article. The 

 spine on the basal article of the antenna reaches to the end of the first article of the anteimule, while 

 the spine of the second article slightly exceeds the third article of the antennule. The smaller cheliped 

 does not bear a brush of hairs. The movable finger of the larger cheliped is heavy, but is not raised into 

 a crest as in S. townsendi. The second pair of legs has the carpal articles in the proportion of 5 , i , i , i , 2 . 



Fig. 5. — Synalpheus minus. Aiter Couti^re. 



a. Front of carapace and appendages; b, second leg; c 

 telson; d, large chela. 



