REPORT ON THE CRUSTACEA MACRURA. 609 



rostrum nearly to its apex ; on the lower surface of the rostrum near the distal extremity 

 there are three teeth, behind which the inferior margin is excavate for the more free 

 play of the ophthalmopoda, a condition that gives a somewhat arcuate appearance to the 

 rostrum. The frontal margin has the orbit nearly conicident with the first antennal 

 tooth, whence it descends vertically to the infradateral margin, the angle being defined 

 by a small tooth ; there are no teeth on the orbital or hepatic regions. 



The pleon is smooth and dorsally rounded, the somites are subequal, the fifth and 

 sixth being the shortest. 



The telson is dorsally flattened, and laterally armed with two small, distantly situated 

 spinules, placed a little within the margins ; it gradually tapers to the extremity, which 

 is furnished with a row of Ions; and slender hairs. 



The ophthalmopoda are cylindrical and about half the length of the rostrum, the 

 stalk being as stout as the ophthalmus. 



The first pair of antennae is biramose ; the peduncle reaching considerably beyond 

 the distal extremity of the rostrum ; the first joint is longer than the ophthalmopod, and 

 supports a strong stylocerite that reaches to its extremity ; the second joint is about half 

 the length of the first, and extends beyond the extremity of the rostrum, and the third 

 joint is short, being scarcely more than half the length of the second. 



The second pair of antennas is about once and a half the length of the animal and 

 tapers to a delicately fine point, and the peduncle supports a scaphocerite that extends a 

 little beyond the peduncle of the first pair of antennae. 



The mandibles and other oral appendages could not be thoroughly examined 

 without destroying the single specimen. 



The second pair of gnathopoda is moderately robust and four-jointed, the terminal 

 joint, reaching beyond the distal extremity of the peduncle of the first pair of antennae, 

 is hirsute and tipped with three strong spinules. 



The first pair of pereiopoda is moderately robust ; the propodos is subequal in 

 length, but not much broader than the carpos, the hand is long, ovate, and terminates 

 in a chela that has subequal fingers ; the pollex and dactylos are convergent, meet at 

 some little distance within the points, and are about half the length of the palm of the 

 propodos. The second pair of pereiopoda is long, slender and minutely chelate ; the 

 carpos, which forms about half the length of the limb, is multiarticulate. The fourth 

 pair of pereiopoda is robust and nearly as long as the second ; the propodos is armed 

 with a row of gradually enlarging spinules on the posterior margin, and the dactylos is 

 slightly curved and biunguiculate. The third and fifth pairs are broken off at the basisal 

 joint. 



The four anterior pairs of pereiopoda support a small mastigobranchia below the 

 margin of the carapace. 



The pleopoda are biramose, the first pair having the inner branch smaller than the 



(ZOOL. CHALL. EXP. — PART LII. 1887.) Fff 77 



