PART 1 GARTH : PACIFIC OXYRHYNCHA 235 



Description: Carapace high in median region; lateral wings broad, 

 ascending; anterior or hepatic lobe much the larger, intervening sinus 

 deep. Posterior margin of hepatic lobe convex, anterior margin transverse, 

 with a lobe or tooth near its middle. Branchial lobe triangular, acute. 

 Rostrum broadly oblong, sides subparallel, extremity bilobed, median 

 sinus broad, shallow. Hand elongate, not widening much until just 

 before the fingers; fingers short and very wide, outer margin acutely 

 carinate. (Rathbun, 1923a) 



Chelipeds of moderate size ; merus very bluntly angled ; carpus and 

 manus with a subacute, outer carina; a tubercle on upper surface of 

 carpus; outer margin of fingers acutely carinate, a large tooth on the 

 dactyl within the narrow gape. Ambulatory legs rather stout; two 

 tubercles on lower margin of proximal half of merus of first leg; pro- 

 podites without tooth or tufts of hair. Third, fourth, and fifth segments 

 of male abdomen fused. (Rathbun, 1925) 



Female similar in all respects to the male except for the less massive 

 cheliped, both merus and manus of which are foreshortened. 



In the young the rostrum is deeply emarginate and has a basal 

 swelling, below which a noticeable constriction delimits it from the 

 prominent preorbital lobes. The anterolateral margin has a supple- 

 mentary inner tooth in addition to the median tooth, and hepatic breadth 

 exceeds branchial. This condition persists in an individual of 7.5 mm. 

 The largest specimens have the rostrum less deeply indented, lack the 

 basal constriction, and have a less prominent preorbital lobe. The inner 

 of the anterior hepatic teeth disappears, as does the tubercle at the mid- 

 point of the superior margin of the manus in the male. In all specimens 

 over 7.5 mm of either sex, the branchial width exceeds the hepatic. 



Material examined: 28 specimens from 9 stations. (See Table 46) 

 From one mile northwest of White Cove, Santa Catalina Island, Cali- 

 fornia, to Entrada Point, Magdalena Bay, Lower California, and in- 

 cluding Guadalupe, Middle San Benito, and Cedros Islands. 



Measurements: Largest specimen, male: length 17.3 mm, hepatic 

 width 14.4 mm, branchial width 15.7 mm, rostrum 3.8 mm, width 3.2 

 mm, cheliped 21.2 mm, chela 10.3 mm, manus 7.4 mm, dactyl 4.5 mm, 

 height of palm 4.5 mm, walking legs 19.2, 15.0, 13.0, and 11.0 mm. 

 Female : length 10.7 mm, hepatic width 9.2 mm, branchial width 9.6 mm. 



Color in life: Unrecorded. 



Habitat: Santa Catalina Island specimens were obtained while mask 

 diving for kelp holdfasts, presumably Eisenia. The La Jolla specimen, 

 according to Robert J. Menzies, was found in an eel grass holdfast in a 



