Boone, Crustacea, Cruise of ''Alva," 1931 47 



surface as the merus, with five or six unequal transverse carinae on 

 the outer surface ; these are replaced on the upper surface by numer- 

 ous coarse denticles and with two large, distal, conical spines. The 

 propodus is greatly compressed, one and two-thirds times as long as 

 the merus, with a median and a distal spine on the upper lateral 

 margin and below this numerous coarse flattish tubercles on the upper 

 fourth of the outer surface, these being replaced on the remainder of 

 the surface by transverse wave-like lines consisting of finer denticles ; 

 the inferior lateral margin has a wide flat carina on the curved basal 

 section and five large, serrate, triangular spines, each one being un- 

 equal sided and forward-directed and with an oblique line of denticles 

 running backward from the tip onto the outer surface of the palm. 

 ,The fixed finger has its carinate lower margin almost at right angles 

 to the palm ; the upper margin is oblique, set with seven or eight un- 

 equal coarse, triangulate teeth, each tapered to an acuminate point. 

 The inner side of the propodus and fixed finger, which are closely 

 oppressed to the body, are rough with wavy transverse, granulose 

 rugae. The hinged finger fits across the distal end of the propodus, 

 closing closely upon the propodal finger, the cutting edge with about 

 five coarse teeth, the tip acuminate, the upper outer margin convex 

 and armed with a series of spinelike teeth, the proximal two of which 

 ;are quite prominent, the others small, semiconcealed by the thick brush 

 of setae that forms a band along the outer half of the inner margin of 

 the upper finger. Similar brushes of setae occur along the inner 

 margins of the cutting edges of both fingers. The chelipeds in their 

 normal resting position, closely appressed to the body, have the fingers 

 above the maxillipeds and these brushes of setae on the fingers form 

 accessory sieves. 



The second, third, fourth and fifth pairs of legs are similar 

 in structure. The first pair have a small spine on the anterior distal 

 angle of the ischium ; the merus is elongate, rounded on the lower sur- 

 face ; both lateral margins are setose ; the carpus, propodus and dactyl 

 are intimately articulated, forming a digging instrument. The carpus 

 is suboval on its outer surface, with bladelike outer margin ; the pro- 

 podus is strong, short and wide, reinforcing the dactyl ; the dactyl is 

 lanceolate-acuminate. The second pair of legs are the smallest of the 

 series ; the third and fourth pairs of legs are subdorsal in position and 

 are larger than the preceding pairs. The third pair of legs has the 

 anterior lateral margin of the carpus and propodus expanded, lami- 

 nate and the hinder lateral margin widely rounded. The dactyl also 



