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



Pasipheea amplidens, n. sp. (PI. CXLI. fig. 2). 



Carapace dorsally straight, rounded, smooth, without a carina ; frontal margin without 

 a rostrum ; frontal region dorsally crested in the form of a sharply pointed, obliquely 

 elevated, and laterally compressed tooth ; it is broad at the base longitudinally, and 

 anteriorly directed. The orbits are but sparingly excavate and imperfectly defined by 

 a small projection. The first antennal tooth is reduced to a prominence, but the second 

 is developed to a large tooth, whence the margin recedes backwards and then at right 

 angles downwards, then rounds off to form the lateral margin of the carapace, which 

 gradually descends posteriorly to near the base of the second pair of pereiopoda, when 

 it is gradually directed upwards. 



The ophthalmopoda are short, standing on distinct pedicles, and distant from each 

 other ; the ophthalmus is globular, of larger diameter than the peduncle, and possesses 

 no ocellus. 



The first pair of antennas has the first joint deeply excavate and furnished with a 

 stylocerite, which is sharply pointed and twisted anteriorly so as to become vertical ; the 

 inner margin is expanded, and flattened by compression against its fellow. The second 

 and third joints are short and cylindrical and carry two flagella, of which the upper is 

 the more robust. 



The second pair of antennas carries a scaphocerite that reaches beyond the distal 

 extremity of the peduncle of the first pair, and is about half the length of the carapace, 

 the inner and outer margin corresponding, each being curved towards the apex, the 

 outer angle of which is furnished with a tooth, and the inner margin is fringed with 

 hairs. 



The mandibles are similar to those of Pasiphasa cristata, but have a larger number 

 of teeth (thirteen) on the incisive margin, and the tooth that forms the lower angle 

 is rather large and somewhat thickened, as if it were the rudiment of the molar 

 tubercle. 



The siagnopoda also closely resemble those of Pasipheea cristata, but there is an 

 interesting variation in the third pair in the more definite distinction of the distal 

 extremity of the appendage from the basal portion, and in the semiarticulated por- 

 tion of the outer basal division being more acutely produced. 



The first pair of gnathopoda is associated with the third pair of siagnopoda, and in 

 form and appearance closely resembles those of Pasipheea cristata. 



The second pair of gnathopoda is long, slender, and pediform ; it carries a stout 

 basecphysis and terminates in a long narrow joint with parallel margins, flattened towards 

 the distal extremity and fringed with short hairs and spinules. 



The first two pairs of pereiopoda are chelate. The first pair is long, slender, and 

 smooth ; the second pair has the posterior margin of the meros strongly serrate, and 



