^THUSA LATA. 35 



slightly curved, longitudinally grooved and ribbed, the upper edge very sharp. 

 The last two pairs of limbs are of about an equal length, not reaching beyond 

 the distal end of the merus of the second pair of ambulatory appendages, 

 pubescent excepting the nail which tips their dactyli ; their propodi are 

 much shorter than the merus and not much longer than the carpus ; dactyli 

 very short and strongly curved. The sternum is rather coarsely granulate. 

 Conspicuous red transverse bands adorn the chelipeds and first two pairs of 

 ambulatory appendages ; there are two of these bands on the merus, one on 

 the carpus, one on the propodus, and one on the dactylus. 



Dimensions of a male : length of carapace, 26.5 mm. ; breadth of cara- 

 pace, 29.5 mm. ; breadth of anterior margin between external orbital 

 teeth, 12 mm. ; length of second ambulatory appendages, 74.5 mm. (merus, 

 12 mm. ; propodus, 15.5 mm. ; dactylus, 22 mm.). 



5 males, 2 fem. 



2 males. 



1 male. 



1 male juv. 



In young small specimens the carapace is not so broad as in the adult (in 

 fact the length of the carapace may be equal to its breadth), the antero- 

 lateral angles do not project so far forward, and the gastric area is not so 

 deeply sunken beneath the level of the branchial regions. 



.ffithusa lata Rathb. 

 Plate VI., Fig. 1, 1% 1". 



Ethusa lata Ratub., Proc. U. S. Nat. Miis., XVI. 258, 1893. 

 Mthusa ptibescens Fas., Bull. Mus. Comp. Zool., XXIV. 160, 1893. 



Station 3367. 100 fathoms. 1 female. 



After examining the type specimens of M. lata Rathb., I am inclined to 

 attribute the slight diflFerences between them and M. puhesce^is to difference 

 in age, the specimen which I described imder the name of ^. pnbeseens being 

 more than twice the size of the type specimens of ^. lata. In the male of 

 ^. lata the right and left chelipeds are very unequal. 



This species was first obtained by the " Albatross " in 1889, in the Gulf 

 of California at a depth of 14-33 fathoms. It is the Pacific I'epresentative of 

 ^. microphthalma Smith * of the Atlantic side of the continent. 



* Proc. U. S. Nat. Mus., III. 41S, 1881 ; VI. 22, 1883. 



