60 Bulletin, Vanderhilt Marine Museiun, Vol. Ill 



tudinal row of eight or ten spines and below this a number of smaller, 

 irregularly spaced spinules. 



The first abdominal segment is short, with a median transverse ele- 

 vation and the epimeral angles acute, up- and out-curved triangles, 

 with the apex scarcely extending beyond the lateral margin of the 

 carapace ; the second to fifth abdominal segments, inclusive, are much 

 longer and wider than the first segment and have the epimera pro- 

 duced to long, acute triangles ; the sixth segment is long but with the 

 epimera forming wider triangles. The telson is slightly wider than 

 long, with the small, lateral lobes rounded and separated from the 

 large median lobe by a notch; the distal margin is broadly rounded 

 and fringed with fine cilia. The rhipidura have a stout peduncle and 

 two broad suboval blades, fringed with cilia ; the outer blade is slightly 

 the wider. In the usual folded-under position of the abdomen, the 

 epimera fit upon each other, forming the sidewalls to a roomy cavity 

 beneath the body in which the eggs and embrj^os are kept. 



The sternal plastron has a strong median groove, the transverse 

 sutures are distinct and there is at the base of the cheliped a strong, 

 acute spine. 



The eyes are on short, flexible, bulbous stallcs, constricted at the base 

 of the cornea, which is large, spherical, composed of many facets. 



The chelipeds are 90 mm. long, the ischium being short, 3 mm. long, 

 and terminating distally in an acute tooth ; the merus is 31 mm. long ; 

 the carpus 20 mm. long ; the propodus 22 mm. long ; the dactyl 14 mm. 

 long; there is a series of sharp, out- and forward-pointing spines on 

 each lateral margin of the ischium, merus, carpus and propodus ; the 

 latter has two additional submedian rows of spines on the upper mar- 

 gin. The fingers are slender, meeting with numerous, sparsely placed 

 long hairs; the cutting edges are set with irregular sharp teeth; the 

 finger tips meet. 



The first, second and third pairs of ambulatory legs are very long 

 and slender and are armed with spines along both lateral margins. 



The fifth legs are small, of the typical small size, reflexed, weakly 

 chelate. 



Synonymy. — Ptychogaster spinifer A. Milne Edwards, Bull. Mus. 

 Comp. Zocil., vol. 8, No. 1, p. 64, 1880; Mem. Mus. Comp. ZooL, 

 vol. 19, No. 2, p. 35, p. 118, pi. 9, figs. 16-22, pi. 10, figs. 4-16, 1897, 

 —Benedict, Proc. U. S. Nat. Mus., vol. 26, p. 334, 1902.— Boone, 

 Bull. Bingham Oceanog. Coll., vol. 1, art. 2. p. 61, 1927. 



