94 MESSES. NORMA.N AND STEBBINa ON THE 



The upper antennae have the first joint long, not flattened out, rather wider at the 

 base, lower parts of the inner margin slightly denticulate, towards its extremity two 

 lone cilia, and beyond these a tactile seta, outer margin with three or four minute 

 tactile sette, and about as many simple cilia: second joint with four long plumose 

 (tactile]) setiE and two simple cilia; tliirdwith two simple cilia; flagellum with 17-21, 

 secondary appendage with 9 articulations ; olfactory filaments of great length, attached 

 to alternate articulations of the flagellum. 



The lower antennee have the scale long and linear, reaching beyond the fourth joint, 

 with only six marginal setae (one on the inner, two on the outer margin, and three 

 apical) : last joint of peduncle bearing two simple cilia at its end and four tactile setae, 

 two of which are much larger than the others ; flagellum of 9-13 articulations. 



The first gnathopods in the male (i. l) have the basos broad, attached to the coxa by 

 a narrow neck, terminating in a tooth at the lower front angle, and having a similar 

 tooth somewhat higher up upon the same margin ; meros triangular, very narrow at the 

 base and rapidly widening, a very large tooth-process on the front margin, articulating 

 with the wrist in a splice-like manner, the lower angle being produced and underlying 

 the wrist, the latter joint is narrowed at the base and lies on the produced tongue of 

 the meros, and bears four cilia and a tooth-process on the front margin ; hand in general 

 form as that of A. simplicirostris, but the portion before the thumb is larger, while the 

 thumb itself is less laterally directed ; the outer margin of thumb carries about seven 

 cilia, and its inner margin has two processes, of which the basal is tubercular, the second 

 large and wide, much elongated, and beyond these processes the edge bears a closely 

 packed series of microscopic flat inclined teeth, by the side of which are about eight 

 stiif cilia (not spatulate as in A. simplicirosfris) ; the finger has a tubercle on the inner 

 margin near the base, is then hollowed for the reception of the large tooth of the 

 thumb, and beyond this is set with numerous short spine-like teeth. The same 

 gnathopod in the female (i. gn^ ? ) is like that of the male in its general character, 

 but is much more slender, the hand much less strong, the thumb and finger meeting 

 throughout their entire length, without the large tubercular processes, while the whole 

 maro-in of the thumb is set with microscopic teeth and cilia similar to those which 

 occupy only the distal portion of the thumb in the other sex. 



The second gnathopods (i. gn^) have the coxal spine narrow and acute, the basos 

 unarmed, ischium very short, meros with a terminal cluster of cilia above, and below 

 with a distal spine and numerous long cilia on the margin; carpus and propodos 

 subequal and shorter than meros, the former with numerous long cilia on both margins 

 and also two spines on the front margin ; propodos with numerous long cilia on both 

 margins (about 8 on the palm), and 5-6 spines on the palm and one distal spine on the 

 back; dactylus bearing on its edge six spinules (i. gn^'), which have little cilia near 

 their tips. The spines of carpus and propodos, examined under a high power, are 

 found to have a peculiar character, the carpal spines are spatulately hollowed at their 



