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



ramus ; outer ramus much shorter than the inner, with two spiues on the margin, and a 

 group at the apex ; inner ramus with three on the margin and a strong group at the 

 apex ; peduncles of the second pair a little longer than the outer, much shorter than the 

 inner, ramus ; the outer ramus about half the length of the. inner, with one spine on 

 the margin and a group at the apex ; the inner ramus with three spines on the pectinate 

 inner margin and a group at the apex ; peduncles of the third pair very short above, 

 scarcely reaching back so far as the peduncles of the other two pairs, but below 

 produced beyond them in a triangular apex ; the outer ramus narrower than the inner 

 and about half its length, with three spines along its margin, the apex acute ; the inner 

 ramus also with an acute apex, rather longer than the inner ramus of the first or second 

 pair, its inner margin pectinate, carrying four or five spines, the outer margin four. 



Telson as long as the peduncles of the third uropods, but not reaching back quite to 

 the end of their produced tips, longer than broad, with a short, but definite, rather 

 dehiscent, cleft, and the apices rounded ; the lateral margins converging slightly ; a 

 ciliuin on either side near the margin, below the centre. 



Length. — The specimen, in the position figured, measured under a quarter of an inch. 



Locality. — Station 313, off Cape Virgins, Patagonia, January 20, 1876; depth, 55 

 fathoms ; bottom, sand; bottom temperature, 47°"8. One specimen. Trawled. 



Remarks. — The specific name refers to the dorsal dentation. A small specimen, 

 remarkably like this species, so far as could be observed, but with the hands of the 

 gnathopods more quadrate, the palms more oblique, was obtained at the surface, February 

 5, ] 875, that is between Stations 212 and 213, at about lat. 6° N., long. 123° E., therefore 

 at an enormous distance from the locality of the specimen described and figured. As 

 in the second specimen the antennae, perseopods, and uropods were broken, it does not 

 seem worth while to go into fuller details about it. 



The present species shows a very great resemblance to Paramphithoe tridentatus, 

 Bruzelius, which Boeck has named Halirages tridentatus ; it is separated from it by the 

 short outer branches of all three pairs of uropods, the somewhat different termination of 

 the telson, as well as by the bilobed upper lip, and some other details of the mouth- 

 organs. From its compatriot, Atylopsis magellanicus, it is distinguished by the dorsal 

 teeth, and by the termination of the telson. 



Atylopsis emarginatus, n. sp. (PL LXXXL). 



Rostrum small, with rounded point ; lateral lobes of the head sinuous, lower angle 

 slightly produced, rounded ; first and second segments of the pleon postero-laterally 

 angled but not acutely, third segment rounded. 



Eyes indistinctly made out, seemingly large, reniform, colourless in spirits. 



