496 PROCEEDINGS OF UNITED STATES NATIONAL MUSEUM. 



Statiou 2224, September 8, 1884, north latitude 36° IG' 30", west lon- 

 gitude 68° 21', 2,574 fathoms, globigerina ooze, temperature 36.8°, one 

 female (8563). 



Mundiopsis sitnilis, sp. uov. 



This species, represented like the last by a single egg-bearing female, 

 is very closely allied to M. crassa, and will possibly prove to be a 

 variety of it. The single specimen is very much smaller than that of 

 crassa, being only about three-eighths as long, but is evidently fully 

 adult if not grown to the full size to which the species attains. 



Female. — The form and proportions of the carapax are almost exactly 

 as in the last species, but all the marginal spines are more slender and 

 the only spines on the dorsal surface proper are a single pair on the 

 anterior part of the gastric region ; the rest of the anterior part of the 

 carapax being only slightly roughened with minute transverse broken 

 ruga?, while the posterior portions^ are armed very nearly as in crassa, 

 though the carina of the posterior margin is proportionally wider and 

 not distinctly double nor sharply crenulated. 



The eyes, antennulae, and antennae are almost exactly as in the last 

 species, and so are the oral appendages, except the merus of the second 

 gnathopod, which is armed with a few scarcely spiniform tubercles in 

 place of conical spines. 



The right chelii)ed is considerably smaller than the left, and is appar- 

 ently a reproduced appendage. The left is considerably more slender 

 and much longer than in crassa, being fully once and two-thirds as 

 long as the carapax, including the rostrum ; the merus is armed along 

 all the angles, except the outer or posterior, as well as at the distal 

 end, with long spines : the carpus is armed dorsally with three spines 

 at the distal end, and with one or two on the inner edge ; the chela is 

 much longer than the greatest breadth of the carapax, a third as broad 

 as long, armed along the inner edge with two or three spines, and has 

 the digits about half the whole length. The ambulatory peraeopods are 

 nearly alike and a little longer than in crassa ; the meri and carpi are 

 armed nearly as in that species, but the propodi each have only a single 

 spine on the dorsal edge. 



The whole dorsal surface of the pleon is nearly smooth, though there 

 is a shallow transverse sulcus on second and third somites. The mid- 

 dle of the posterior margin of the sixth somite is truncated and less 

 prominent than the small lobe on either side. 



The eggs are apparently considerably smaller than in crassa, meas- 

 uring 2.7 by 2.9°*°" in the recently preserved alcoholic specimen. 



Station 2192, August 5, 1884, north latitude 39o 46' 30", west longi- 

 tude 1(P 14' 45", ] ,060 fathoms, globigerina ooze, temperature, 38.6o, 

 one female (8255). 



