748 THE VOYAGE OF H.M.S. CHALLENGER. 



The ophthalinopoda are short and flattened. 



The joints of the peduncle of the first pair of antennae are short and support a 

 flagellum that is about as long as the carapace. 



The second pair carries a scaphocerite that reaches to the extremity of the rostrum ; 

 it is broad at the base and gradually tapers to the distal extremity, where it is furnished 

 on the outer margin with a small tooth. The flagellum in both specimens is broken 

 short off. 



The second pair of gnathopoda is a long and powerful organ, pediform in shape, and 

 has the terminal joint long, robust, and styliform. 



The second pair of pereiopoda is longer and more slender than the first, and the three 

 following are furnished with small but well-formed spines along the posterior margins of 

 the ischium and meros, but none on the carpos or propodos ; the latter joint is straight, 

 slender, and terminates in a dactylos that is long and styliform in the third and fourth 

 pairs, but short and almost rudimentary in the fifth pair. 



The first pair of pleopoda carries a small bud-like branch, attached to the inner and 

 anterior side in the female, but produced to a larger leaf-like plate, somewhat truncate at 

 the extremity, in the male. 



The telson (fig. lz) is broad at the base and tapers to the extremity, which is on a 

 level with the inner plate of the rhipidura. The dorsal surface is rounded and free from 

 any carina, the sides are compressed and smooth, having no teeth or spines except at 

 the extremity, which is furnished with three or four short spinules. 



Acanthephyra carinata, n. sp. (PI. CXXVI. fig. 2). 



Dorsal surface carinated from the rostrum to the telson. Rostrum about half the 

 length of the carapace, anteriorly slightly elevated, dorsal surface and crest armed with 

 six or seven short teeth ; under surface armed with one tooth near the middle and im- 

 mediately below the most anterior tooth on the upper, whence the rostrum is smooth to 

 the apex. On each side of its base the rostrum is strengthened by an obliquely horizontal 

 ridge. The dorsal carina dies out just within the posterior margin of the carapace, but 

 is reproduced on the first somite of the pleon. 



The first somite of the pleon is anteriorly smooth and posteriorly carinated. All 

 the other somites are carinated, and the third, fourth, fifth, and sixth are posteriorly 

 produced to a sharp tooth. 



The telson (fig. 2z) is dorsally carinated on the anterior half and terminates pos- 

 teriorly in a central tooth, flanked by three smaller ones. 



The ophthalmopoda (fig. 2a) are short, broad, and furnished with a small ocellus. 



The first pair of antennas is about half the length of the animal and is furnished with a 

 stylocerite that equals the length of the first joint. 



