NO ii:»c. on.'^fCRrArio.xs ox the astacidjs—faxon. Gfil 



inore stroiioly developed; tlie postorbital ridges bear distinct aiitciior 

 sj)iiios; the liiuid is broader and more hirsute, and the tiiigers are 

 tipped with more conspicuous, yellow, corneous nails. 



Length 38 irtm. 



State of Guanajuato, Mexico, A. Duges (No. 16087, U.S.N'.M.). 



CAMBARUS MONTEZUMiE AREOLATUS Faxon. 

 (PlatoLXVI, fig. 2.; 

 Camharns montczunur, var. areoJata Faxon, Rev. Astacidnc, Pt. 1, 1885, p. 123. 

 In this form the outline of the rostrum is similar to that of C. m, 

 diKjesii, but the lateral margins are not .raised so as to form prominent 

 carina'. The lateral rostral spines and the spines at the anterior end 

 of the postorbital ridges are developed to about the same degree as 

 in C. m. (lugesii. The characteristic feature of this form is the short- 

 ness of the posterior section of the carapace, which involves a very 

 short and broad areola, 



Parras, Coahuila, Mexico, Edward Palmer (No. 3G50, Mus. Comp. 

 Zool.). 



CAMBARUS MONTEZUMiE OCCIDENTALIS, new subspecies. 

 (Plato LXVI, ligs. 3, 4.) ' 

 Camharus montczunur Faxox (pars), Rev. Astacid;p, Pt. 1, 1885, p. 123. 



Eostrnm plane above, margins but very slightly raised, tapering grad- 

 ually from the base to the tip without distinct lateral spines or defi- 

 nitely limited acumen. It reaches at the most to the distal end of the 

 second antennular segment. Postorbital ridges unarmed. 



Mazatlau, Mexico (No. 3052, Mus. Comp. Zool.). 



CAMBARUS CHAPALANUS, new species. 

 (Plate LXVII, fio-s. 1,2.) 



Similar to C.montezuma\ hut differs in the following regards: Body 

 slenderer and more cylindrical; rostrum much longer aiul narrower, 

 reaching to the end of the antennular i)eduncle, somewhat hirsute, 

 armed with a pair of stout and shar]) lateral spines, and a long' spiui- 

 form acumen; postorbital ridges terminating anteriorly in long and 

 strong spiniform teeth; antennal scales mu(th longer and narrower and 

 armed with a much longer apical spine. 



Type. — Lake Chapala, State of Jalisco, IMexico, P. L. Jouy (No. 17098, 

 U.S.N.M.). One male. 



Same locality and collector (No. 1G294, U.S.N.M.), Three males. 



The upper surface of the rostrum is plane, with raised lateral mar- 

 gins. The sides of the rostrum are convex, distinctly converging 

 before attaining to the lateral spines. The chelipeds and the male 

 sexual organs are like those of the typical form of C. montezuma'. 



