PART 1 GARTH : PACIFIC OXYRHYNCHA 369 



Mithrax (Mithrax) bellii, Rathbun, 1925, p. 403, pis. 142, 143. Boone, 



1927, p. 155, fig. 49. Garth, 1946, p. 389, pi. 66, figs. 1, 2. 

 Mithrax belli, Hult, 1938, p. 11. 



Types: Two adult females, cotypes, length and width about 50.8 

 mm, and young of both sexes, originally deposited in the Museum of the 

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



Type locality: Galapagos Islands, 6 fathoms; Hugh Cuming, col- 

 lector. 



Localities subsequently reported, with collectors: Galapagos Islands: 

 Albemarle Island, Hopkins-Stanford Expedition (Rathbun, 1902b) ; 

 Chatham Island, Albatross (Rathbun, 1907) ; Eden Island, Noma 

 (Rathbun, 1924b) ; Hood Island, Arcturus (Boone) ; Indefatigable 

 Island, R. Blomberg (Hult) ; also Charles, Barrington, Seymour, Tower, 

 James, and Onslow Islands, Velero HI (Garth). Not Chile (Miers). 

 (See Remarks below.) 



Atlantic analogue: Mithrax (Mithrax) verrucosus Milne Edwards. 



Diagnosis : Rostral lobes tuberculiform. Lateral margins of carapace 

 with numerous lumpy projections. Basal antennal article with a knob 

 similar to rostral tubercle. Carapace densely paved with close-set gran- 

 ules. Wrist tuberculate above. Male abdomen broad ; male first pleopod 

 consisting of a swollen basal portion and a long tubular extension with 

 the opening at the tip. A large species. 



Description: Carapace convex, broadly ovate [correction for ornate], 

 a little broader than long. Surface covered with flattened granules and 

 very unequal tubercles, closely crowded and forming a continuous pave- 

 ment. Margins thick, projections coarsely rounded. Rostrum with two 

 thick, rounded horns separated by a V-shaped space, and two pairs of 

 dorsal tubercles. Knob at the angle of the basal antennal article curved, 

 larger than either rostral horn and on a higher level. Preorbital lobe 

 tuberculiform, not prominent. Orbital margin with two other, smaller 

 tubercles above, one, not prominent, at outer angle, and one below, 

 besides a submarginal tubercle or blunt spine on the basal antennal article, 

 conspicuous in dorsal view. Just behind and between the orbits two lon- 

 gitudinal rows of two or three tubercles each, and further back a trans- 

 verse, sinuous line of five tubercles. On the lateral margin six tubercles, 

 the first and second large and bearing an accessory, anterior tubercle, the 

 first hepatic, the second largest of all, the third largest of the simple 

 tubercles, the fourth smallest, the sixth postlateral. Further back on the 

 postlateral margin a row of minor tubercles. On the subbranchial, sub- 

 hepatic, and suborbital regions a row of tubercles, some visible in dorsal 



