SHRIMPS OF THE GENUS BETAEUS — HART 445 



Betaeus ensenadensis Glassell 



Figures 23-25, 28, 35, 36, 43-45 



Betaeus, new species, MacGinitie, 1934, pp. 173-174; 1937, pp. 1035-1036. 



Betaexis ensenadensis Glassell 1938, pp. 416-419, pi. 28 (type locality, Estero de la 

 Punta Banda, Ensenada, Baja California, Mexico; holotype male, San Diego 

 Soc. Nat. Hist. No. 1121).— MacGinitie and MacGinitie, 1949, p. 279. 



Female. — Carapace laterally compressed but without carina; 

 smooth, naked. Front (fig. 23) shghtly curved, depressed anteriorly. 

 Anterior margin without sinuses or with shallow ones. Anterolateral 

 angle obtuse (fig. 24). Width of carapace increases rapidly to base of 

 third maxilliped, followed by slight undulation over base of first legs. 

 Posterolateral region rounded. Blunt angle beneath cardiac notch. 



Abdomen smoothly rounded with posteroventral margins of pleura 

 of first four segments rounded, fifth bluntly angled. Ventral margin 

 of first pleuron sparsely setose. 



Telson (fig. 28) subequal to sixth segment, nearly twice as long as 

 wide, with outer margins slightly undulate. Two pairs of movable 

 spines on dorsal sm'face, two spines at each posterolateral angle, outer 

 ones very small. Posterior margin slightly curved, armed with plu- 

 mose setae. 



Eye somewhat oval, with small flat tooth on eyestalk. 



Antennule with stout scimitar-shaped stylocerite, reaching to about 

 distal third of second segment of peduncle. Subterminally first seg- 

 ment of peduncle produced into thin tooth ventrally. Second segment 

 of peduncle longer than fu'st, which is longer than third. Flattened 

 fused part of outer flagella shorter than peduncle; distally divided 

 into few free segments and slender flagellum subequal to fused portion. 

 Inner flagellum considerably longer. 



Antennal peduncle subequal to antennular peduncle, with ventral 

 distal part of basis produced into sharp tooth. Scale (fig. 25) with 

 spine much longer than narrow blade, slit between minute; outer 

 margin almost straight. Scale reaching to middle of third segment of 

 antennular peduncle. Flagellum short, wide, much flattened, reaching 

 slightly past posterior margin of carapace. 



Thu'd maxilhped reaching to middle of second joint of antennular 

 peduncle. Ischiomeropodite sparsely setose, slender, flattened, some- 

 what curved, subequal to two distal segments together in length. 

 Exopodite longer than ischiomeropodite, relatively stout. Penulti- 

 mate segment shortest, sparsely setose. Distal segment banded 

 medially with many short bristles. 



First legs (fig. 35) similar. Ischium short with ridge flatly tubercu- 

 lated ventrally. Stout merus with deep groove into which second leg 

 fits. Two evenly toothed ridges ventrally, transverse sulcus distally. 



