REPORT ON THE CRUSTACEA MACRURA. 749 



The second pair of antennas is longer than the animal, and supports a broad scapho- 

 eerite that terminates in a sharp point. 



LeDgth, entire (male), 



„ of carapace, 



,, of rostrum, 



,, of pleon, . 



„ of third somite of pleon, including tooth (1 mm.), 



,, of sixth somite of pleon, 



„ of telson, 



Habitat— Station 310, January 10, 1876; lat. 51° 27' 30" S., long. 74° 3' 0" W.; 

 Sarmiento Channel, Patagonia ; depth, 400 fathoms ; bottom, blue mud ; bottom temper- 

 ature, 46° "5. One specimen, male. Trawled. 



This is one of the largest species of the genus, and is noticeable from having the 

 carina on the first somite of the pleon, or at least on the posterior half, whereas in all 

 other species this somite is free from great compression or dorsal elevation. The carina on 

 the carapace extends to within a short distance of the posterior border, and is marked by 

 a notch above the cardiac region. The rostrum is short, being only half the length of 

 the carapace, and is styliform and slightly elevated anteriorly. 



The scaphocerite is about the same length as the rostrum, and terminates in a sharp 

 point formed by the tooth that arms the extremity of the outer margin. It is broader 

 at the base than in most species, and the tooth on the distal angle of the second joint is 

 sharp, strong, and furnished with long hairs on the lower surface. 



The two anterior pairs of pereiopoda are slender and chelate. The two following are 

 slender and terminate in a styliform dactylos, and the posterior pair is short. None of 

 them have teeth or spines on the ischium or meros, but only a fringe of hairs. 



Acanthephyra acutifrons, n. sp. (PI. CXXVI. fig. 3). 



Carapace laterally compressed and dorsally carinated in its entire length but especially 

 over the frontal region, which is produced to a short, strong, sharp, laterally compressed 

 rostrum, reaching nearly to a level with the extremity of the scaphocerite ; the under 

 margin is furnished with a denticular prominence, from which point to the base there is 

 a longitudinal brush of hairs ; the dorsal crest is armed with eleven teeth, which extend 

 from the gastric region to half the length of the rostrum. 



The dorsal surface of the pleon is carinated from the first to the last somite, and the 

 four posterior somites are each posteriorly produced to a strong tooth, of which the 

 anterior is the most important. 



The telson is without a carina and is slightly grooved in the median line ; it is armed 

 on each side with three or four small spinules, and four on the terminal extremity. 



