THE SPIDER CRABS OF AMERICA 333 



LISSA AURIVILLIUSI Rathbun 



Plate 246, fig. 2 



Lissa aurivilliusi Rathbun, Proc. U. S. Nat. Mus., vol. 21, 1898, p. 575, 

 pi. 41, fig. 4 (type-locality, off Cape St. Lucas, 31 fathoms; holotype, 

 Cat. No. 21575, U.S.N. M.); Proc. Washington Acad. Sci.. vol. 4, lbo2, 

 p. 284. 



Diagnosis. — Branchial ridge narrow; postero-lateral margin con- 

 cave; one crest on carpus of first three pairs of ambulatory legs. 



Description. — Gastric prominence small, angular; oblique ridges 

 leading from it sharp, finely tuberculate, with only a shallow tooth at 

 middle in place of the round knob in L. taherosa and terminating in a 

 raised tooth at postero-lateral angle. Cardiac hump small, median 

 ridge extending back from it narrow. Lateral margins tuberculate, 

 a shallow tooth at middle and one farther back. Postero-lateral 

 margin with a shallow sinus extending its whole length. Median 

 notch of front shallow, outer teeth prominent. 



Chelipeds much as in L. iuherosa. Ambulator}^ legs with only one 

 crest on the carpus of the first three pairs, the anterior crest of L. 

 tuberosa being represented by a tooth. 



Measurements. — Male, holotype, length of carapace 12.5, width 13 

 mm. Immature female, length of carapace 9.8, width 10 mm. 



Range. — West coast of Lower California, Mexico; Galapagos 

 Islands. To a depth of 31 fathoms. 



Material examined. — ■ 



Magdalena Bay, Lower California; lat. 24° 32' 00" N.; long. 111° 

 59' 00" W.; 12 fathoms; fne. gy. S.; May 2, 1888; station 2831, 

 Albatross; 1 female (21928). 



Lower California; off Cape St. Lucas; lat. 22° 52' 00" N.; long. 

 109° 55' 00" W.; 31 fathoms; rky.; temp. 74.1° F.; May 1, 1888; 

 station 2829, Albatross: 1 male holotype (21575). 



Galapagos Islands; reef N. of Tagus Hill, Tagus Cove, Albemarle 

 Island; Mar. 16, 1899; Stanford Univ.; 1 male (25674). 



LISSA TUBEROSA Rathbun 



Plate 246, fig. 1 



Lissa tuberosa Rathbu.v, Proc. U. S. Nat. Mus., vol. 21, 1898, p. 574, pi. 

 41, fig. 3 (type-locality, southern part of Gulf of California, 8 fathoms; 

 holotype. Cat. No. 21574, U.S.N. M.). 



Diagnosis. — -Carapace nodose; two large branchial protuberances; 

 postero-lateral margin sinuous; two crests on carpus of ambulatory 

 legs. 



Description. — Surface covered with a dense, short, vascular pubes- 

 cence. Carapace with two median tuberculated prominences, gastric 

 higher tlian cardiac, which is continued along median line to pos- 

 terior margin. Ridge running obliquely backward from gastric prom- 

 5487— 25t 28 



