REPORT ON THE AMPHIPODA, 677 



convexities of the lower and hind margins of the third segment meet in a less-rounded 

 angle. 



Eyes not clearly perceived, but probably large. 



U'pper Antennse as in Orchomene musculosus. 



Loiver Antennie similar to those in the species just named, but the third joint as long 

 as the fifth, the fourth longer than either ; the flagellum of fifteen joints. 



Upper Lip. — Front margin rounded in lateral view, apex strongly furred below. 



Mmidihles as in Orchomene musculosus, but having the trunk narrower behind the 

 palp ; the second joint of the palp more elongate, with eighteen to twenty spines on the 

 upper part ; and on the third joint three and twenty spines on the front margin. 



Lower Lip and Maxillse as in the kindred species. In the first pair of maxillae the 

 spines on one maxilla do not appear to agree exactly in dentation with those on the 

 other, and in the two species some variation would probably be found upon a comparison 

 of spine with spine. 



Maxillipeds differing but slightly from those of Orchomene musculosus, the little 

 marginal teeth of the outer plates being only eleven in number, the first joint of the 

 palp rather less developed ; the slender terminal joint has two ciha beside the slender 

 spine-like nail, one on the pectinate inner margin not far from the nail, and a longer one 

 on the outer margin also not far from the nail ; near the base is a small depression on 

 the outer margin, but without a cilium present in our specimen. 



First Gnathop>ods. — Side-plates longer than broad, a little widened below, scarcely 

 produced forwards, front margin nearly straight. First joint reaching beyond the side- 

 plate, as long as the rest of the limb, not broad or expanded at any part ; the remainder 

 of the limb not massive as in Orchomene musculosus, but otherwise showing a remarkable 

 similarity in detail ; the pectination of the palm differs a little in the two species, but 

 this minute character might vary in difi"erent specimens of the same species. 



Second Gnathopods with the hand rather longer than the third joint, its hinder 

 margin concave, strongly produced to antagonize with the minute finger, the very oblique 

 lower margin being set with eight or nine curved spines, so graduated that in one of the 

 gnathopods their tips presented an even line in continuation of the hinder margin of the 

 hand. These spines are partially serrate on the inner side, and have an accessory thread 

 at the tip, giving the tip a rather ragged appearance. The limb in general resembles that 

 in Orchomene musculosus, and has the same delicate furring of the wrist, but the hand is 

 considerably more produced, so as to be on a minute scale chelate rather than subchelate. 



First Peneopods. — Side-plates long and narrow, of almost even width throughout. 

 First joint reaching just to the end of the side-plate, shorter than the second and third 

 united. 



Second Perxop)ods. — Side-plates a httle longer than those of the preceding pair, not 

 double the width at the acute lower angle of the hinder excavation. First joint not 



