352 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 5 



Habitat. — Rocky shore ; occasionally in Pocillopora coral. 



Depth. — Shore to 30 fms ; rarely to 70 fms. 



Remarks. — ^With no other Galapagos species of Brachyura is the field 

 collector so likely to be misled as to identity as with D. Ursula. Unless he 

 notices that the fourth pair of walking legs are reduced to minute size and 

 carried dorsally, he will believe himself to have found a species of 

 Pilumnus. In the preliminary sorting of the Hancock Brachyura, all 

 Dynomene were placed with the Xanthidae and retained by the writer 

 instead of being placed with the oxystome crabs consigned to the National 

 Museum, and they had to be sent for later in order to be included in the 

 Rathbun monograph of 1937. 



In view of the fact that D. ursula is one of the very few oxystomatous 

 and allied crabs taken commonly in shore collecting, it is surprising that 

 it had not been collected in the Galapagos Islands previous to the Hancock 

 Expeditions, which found it to outnumber such common nonoxystomatous 

 species as Herbstta edwardsi Bell and Ozius perlatus Stimpson. 



Subtribe OXYSTOMATA 



Family DORIPPIDAE 



Genus ETHUSA Roux, 1828 



Ethusa lata Rathbun 



Plate 60, Fig. 3 



Ethusa lata Rathbun, Proc. U.S. Nat. Mus., vol. 16, p. 258, 1893; Bull. 

 166, U.S. Nat. Mus., p. 84, pi. 24, fig. 1, pi. 25, fig. 1, pi. 28, fig. 3, 

 text fig. 19, and synonymy, 1937. Crane, Zoologica, vol. 22, no. 7, 

 p. 105, 1937. 



Type locality. — Gulf of California, 33 fms. 

 Type.— USNM No. 17483. 



Range. — From 20 miles south of San Roque Island, Lower California 

 (Glassell), to La Plata Island, Ecuador (Velero III) ; Galapagos Islands 

 (Velero III). 



Atlantic analogue. — E. Tiiicrophthabna Smith. 



Diagnosis. — First and second ambulatory legs stout, dactyls flattened, 

 long as meri ; last two pairs slight, dorsally placed, bearing hooked dactyli. 

 Eyestalks very short, not extending beyond outer orbital spine. First 3 

 abdominal segments visible dorsally. 



Material examined (13 specimens from 5 stations). — 

 147-34. Tagus Cove, Albemarle Island, 30 fms, Jan. 13, 1934, 1 young 



(USNM No. 69180). 

 201-34. Off Gardner Bay, Hood Island, 25-35 fms, Jan. 31, 1934, 1 

 male ( AH F no. 34026). 



