Boone, Crustacea, Cruises of "Ara" and "Alva" 265 



distally, while in the more concave portion between the carina 

 and anterior margin there are also two spines in transverse 

 series proximally and one, or none distally; these series being 

 repeated throughout the length of the dactyl. These two articles 

 of the second left ambulatory leg are not "very elegantly tes- 

 salated by a series of deep cut and extremely regular transverse 

 grooves," as defined and illustrated for P. setifer by Dr. Alcock. 

 In the present species about 0.9 of the spines have the whitish 

 bases much enlarged; in the non-marginal spines this enlarge- 

 ment most frequently has the form of convex, circular dome- 

 shaped base, from the center of which the thorn-like, procurved, 

 distal portion arises. Some such dome-like large tubercles lack- 

 ing the thorn-like distal portions occur on the interstices between 

 the spines. 



This species, Pagurus cataphractus Boone, belongs in the 

 Indo-Pacific group of Pagurus, of ichich P. setifer,^ P. Euopsis*^ 

 and P. fabimafius' are members, all having the inner distal 

 angle of the articles of the distal half of the antennal flagella di- 

 lated and the propodite and dactyl of the second left ambulatory 

 leg expanded and distinctively sculptured. The present species 

 is very closely related to setifer H. Milne Edwards, from which 

 it differs in the above cited specialization of the second left am- 

 bulatory ; in the greater abundance and different arrangement of 

 setae on the chelipeds and ambulatories, those of the present 

 species never forming wreaths at the base of the spines as in 

 setifer, in their abundance more resembling P. euopsis Dana 

 from which the present species differs in the sculpture of the 

 third left leg and other important characters. Pagurus cata- 

 phractus Boone differs from P. fahimanus in the greater spi- 

 nosity of the chelipeds, the different sculpture of the second left 

 ambulatory leg and the presence of spines on all the legs, which 

 in P. fahimanus are scabrous only. The ratio of length between 

 the eyestalk, antennular peduncle and antennal peduncle of the 

 present species is also a character which differentiates it from 

 each of the above-named species. 



'Pagurus setifer Henri Milne Edwards, Ann. Sci. Nat. Zool., Paris, ser. 2, t. VI, 1836, p. 274. 

 — Alcock, A., Calcutta Mus., Cat. Indian Decapod Crust., pt. II, Anomura, Fasc I, Pagurides, 

 1905, p. 83, pi. 8, fig. 3. 



^Pagurus euopsis Dana, J., Proc. Acad. Nat. Sci. Phila., 1852, p. 7; also in Wilkes, C, U. S. 

 Explor. Exped. Crust. Vol. XIII, pt. I, 1852, p. 452, atlas XIII, pi. 28, fig. 6 a-c. 



''Pagurus fahimanus Dana, J. D., Proc. Acad. Nat. Sci. Phila., 1852, p. 270; also he. cit. 

 1852-b, p. 454, pi. 28, figs. 7 a-c. 



