832 THE VOYAGE OF H.M.S. CHALLENGE!*. 



continuous to the posterior margin of the carapace, whereas in Notostomus patentissimus 

 it terminates just behind the orbit, while the orbital carina, which commences just below 

 it in the lower or outer margin of the orbit, proceeds independent of the rostral carina, 

 there being a notch separating the two, to the posterior margin of the carapace. A close 

 inspection of Notostomus perlatus shows that the orbital carina, although connected with 

 the rostral carina, yet branches off into a second less important ridge to the outer canthus 

 of the orbit ; in the depression between the two carina? the opththalmopod is capable of 

 being lodged when thrown backwards, and is thus protected, while at the same time a 

 more extensive range of vision is obtained. 



The outer and upper flagellum of the first pair of antennae is not quite so broad as in 

 the preceding species, and the stylocerite is shorter, while the flagellum of the second 

 pair is longer, and the scaphocerite more ovate, being shorter and broader, and also 

 narrower at the apex. The rest of the animal corresponds very closely with the generic 

 condition. 



Notostomus brevirostris, n. sp. (PI. CXXXIV. fig. 3). 



Carapace corrugated on the surface, dorsally arched, and laterally compressed to a 

 carina that reaches to near the extremity of the rostrum, which is short, and armed with 

 five small denticles below and a series above, of which only three are on the rostrum, 

 the rest being on the dorsal carina and continuous to the posterior margin of the 

 carapace. The lateral carinas are as in Notostomus perlatus. 



The pleon is dorsally carinated, and the four posterior somites are each produced 

 posteriorly to a strong tooth. 



The telson is dorsally fluted and tapers gradually to a point that reaches as far as the 

 extremities of the outer plates of the rhipidura. 



Habitat.— Station 120, September 9, 1873; lat. 8° 37' S., long. 34° 28' W.; off 

 Pernambuco ; depth, 675 fathoms ; bottom, red mud. One specimen. Trawled. 



This species bears a close resemblance to Notostomus perlatus, but the only specimen 

 we possess has the rostrum a little shorter and less sharp ; in Notostomus perlat us 

 the little denticles are coarser on the rostrum and more closely implanted on the fronto- 



