400 A. E. Vet- rill Decapod Crustacea of Berntinin. 



Mithrax (including 



AY// to the Bernunlii S t ;-i,'x f MHIini.r <i,nl tome ollieil 

 (Modified from tliat ..f Miss R;itlilinn). 



A. Carapace without oblique, parallel. branchial groove 



B. Mantis of chelipeds sphmlose. Carapace with conical spines ; not setose. 



a. Two distal segments of ambulatory legs stout, very setose; spines of 

 manus in one dorsal row . ......... ........... . ........ >/</. .os/ssi'//! us 



a', Two distal segments of ambulatory h--s Ion- mid slender. sparsely liai.'y. 

 Spines of manus in two dorsal rows.. _____ ..................... cor no In* 



B'. Manus smooth, without spinules. 



C. Rostral horns short, blunt or tuberculitYrm. 



D. Spines or tubercles of anten. lateral margin four, behind orbitals, simple or 



bifid : basal joint of antenna- with inner tooth longest. 



E. Carapace not multi-tubeivnlate; carpus often nearly smooth : meru- of cheli- 



peds multispiiiose: liasal joint of antenna' narrow, with two denticles -Aisputua 

 E'. Carapace and carpus of cheliped- tulien-ulate ; merii- spinnse : rostral horns 



about as lon^' as broad, obtuse ; basal joint of antenn.i- wider, with two 



acute spines ..... . ..... . ................. .................... |./.V/r.ss >) 



C'. Rostral horns lon^ and slender.. . ............................. <n-uH<-<>r,iix 



A', t'aj-ajiace with oblitjue, parallel, branchial ;^roo\ e- : aiiler,, lateral margins 



with four acute spine-: carapace broader than lon;^ in adults /.-yrc/;s (liirl i/ii's \ 



Mithrax cornutus Sau-sure. Curni rml., ];, ./ Spider f,ui,. 



Mitlini.'- 1-ai-nnlnx Saussure. Mem. Crust, nonv. Me.x. et Antilles, p. ?. 1S.")S. 

 A. M.-Edw., Miss. Sci. Mex., v, i, }>. '.'?. pi. xxii, ls?-Y 



FIGURE 38. 



This species grows to rather large size in the \\Yst Indies. Tin- 

 only Bermuda specimen known is young. 



It closely resembles Jf. $pi/wsisxitni<x of the West Imlies* in tin- 

 form and spinulation of the carapace ami chela*, but it can easily be 

 distinguished by the longer and more slender chelipeds and legs, and 

 especially by the far more slender distal two segments of the ambu- 

 latory legs, which are nearly destitute of spines and have only 

 short, sparse hairs, while in the latter these segments are stout, not 

 abrupt!}* attenuated, and are thickly covered with strong dark 

 colored hairs. 



In both species the merus and carpus of the chelipeds are covered 

 with numerous strong and acute curved spines ; in this species the 

 merus is longer and has about eight or nine very acute spines on the 

 posterior border, and near them another irregular row of nearly the 



* This species is likely to occur on the rough grounds outside the Bermuda 

 reefs. Hence I have given the most obvious distinctions here. 



