164 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL.21 



Othonia mirabilis, Gerstaecker, 1857, p. 113 (part). Cano, 1889, pp. 



102, 182. Not Cancer mirabilis Herbst. 

 Othonia sexdentata, Stimpson, 1860b, p. 192. A. Milne Edwards, 1875, 

 p. 117. 



Type: Female, length 19.1 mm, width 16.9 mm; originally in the 

 Museum of the Zoological Society [London], no longer extant. 



Type locality: Galapagos Islands, 6 fathoms, sandy mud; Hugh 

 Cuming, collector. 



Localities subsequently reported, with collectors: Mexico: Lower 

 California: Cape San Lucas, John Xantus (Stimpson) ; A. Milne Ed- 

 wards (Rathbun, 1925). Gulf of California: Santa Inez Point, Zaca 

 (Crane, 1937) ; Coronado[s] Island, Pt. Marcial Reef, and San Gabriel 

 Bay, Espiritu Santo Island, Steinbeck and Ricketts (Steinbeck and 

 Ricketts). Costa Rica: Port Parker, Zaca (Crane, 1947). Ecuador: 

 Galapagos Islands: Floreana [Charles] Island, Vettor Pisani (Cano) ; 

 A. Wollebaek (Sivertsen). 



Atlantic analogue: Pitho mirabilis (Herbst). 



Diagnosis : Carapace thickly and finely granulate and pubescent. Six 

 lateral teeth, the second and third not united at base, all teeth of uniform 

 size except last, this tooth smaller and situated at a higher level. First 

 free antennal segment not remarkably broadened. Male first pleopods 

 closely approximated at midpoints, narrowly lyrate distally. 



Description: Male: Fronto-orbital distance narrow. Rostral teeth 

 very narrow and sharp or spiniform. Lateral teeth of carapace divided to 

 their bases, acute, margins granulate; the sixth or -posterior tooth 

 posterolateral, separated from the fifth tooth by a tubercle and situated 

 above the margin, forming an arcuate line with the other teeth but above 

 their level. Granules and tubercles of carapace more numerous than in 

 Pitho quinquedentata ; about 50 small granules on the cardiac region 

 and 40 on the mesogastric region ; the granules of the postbranchial region 

 large and spinous. One or more hairs curved at tip arising from each 

 tubercle or granule. An uninterrupted row of large transverse tubercles 

 above margin. Orbital teeth acute, the outer one advanced nearly as far 

 as the inner. First movable article of the antenna shaped much as in 

 P. quinquedentata. Chelipeds weak; manus compressed, margins taper- 

 ing toward extremity. (Rathbun, 1925, of a male from Cape San Lucas 

 in the Paris Museum) 



Female: Carapace broadly oval, moderately elevated, the surface 

 rough, granulated, and slightly hairy; the lateral margin with six flat- 

 tened, triangular, falciform teeth, the points acute and directed forwards ; 



