A.MPHIPODA. 245 



Urothoe, Dana, 1852. 

 Urothoe spinidigitus,* n. sp. Plate I., figs. 9. 



Cheval l'aar; November, 1902. One male, length 4 millims. 



Body rounded, as deep as wide. Pleon segments all rounded behind. 



Eyes very large, contiguous above, round, with large facets, red (fig. 9. a). 



Upper antenna? : 1st joint about three-fourths as long and twice as wide as the 2nd. 



Lower antennae : 1st joint very short, 2nd considerably longer than the 3rd ; 

 widening distally, setose on the upper and outer margins, and with an irregular row 

 of spines (longer and sharper at the distal end) on the lower outer margin ; 3rd joint 

 swollen in the middle, with calceoli on the upper margin, and 7 or 8 long and weak 

 seta? below. Flagellum very long and slender (fig. 9. a). 



Mandibles normal; the last joint of the palp with 6 setae on the distal half and one 

 or two very long setae at the tip. 



Maxillipeds : inner plates reaching half way up the outer, narrowed distally and 

 crowned with 2 strong spine-teeth and one or two intermediate setules. Outer plates 

 with curved spines and intermediate setae ; they barely reach the end of the 2nd 

 joint of the palp, which is very broad. 



First and 2nd gnathopods : side-plates very small, the 1st acutely angled in 

 front, the 2nd rectangular, both without setae. The limbs are similar in form and 

 armature, the 2nd pair being rather the larger ; the 1st joint is pyriform, as long as 

 the hand and wrist ; the 2 next short, with very long seta? on the hind margin of the 

 2nd, as also on the distal portion of the 1st. The wrist is rather longer than the hand 

 in the 1st pair and subequal to it in the second this joint and the hand are of the 

 usual form, the hand being widest in the middle ; the palm of the hand is defined by 

 a peculiar rod-like spine, the end obliquely truncate with a setule at the tip ; 

 that of the 1st pair is half as long as the 2nd. The wrist is clothed with long setse 

 oil the pi'ojecting portion, and the hand just below the palmar spine on the hind 

 margin. Dactylus slender, with a setule on outer margin near the point (tig. 9. gn. 1 ). 



Side-plates of the 1st peraeopods small, irregularly oblong ; 1st joint rather longer 

 than 3rd and 4th, the 3rd longer than the 4th, which has 4 blunt spines on the hind 

 margin ; 5th joint shorter and much narrower than the 4th, dilated and rounded at 

 the end, where there are 4 spines of unequal length on the hind margin and 2 very 

 short ones at the base of the dactylus. The dactylus is straight and slender, with 

 5 denticles on the inner side, the one nearest the point being the largest (fig. 9. pp. 1 ). 



Third peraaopods : the 1st joint has the upper part projecting behind with 7 or 8 

 marginal setae ; front margin almost straight ; 2nd joint very short ; 3rd twice as 

 long as 2nd, with a row of blunt spines just above the lower margin and 4 or 5 

 plumose seta? on the hind margin; 4th greatly expanded, with 2 parallel transverse 

 ridges bordered with strong blunt spines and very long plumose setae; 5th longer 



* From the peculiar character of the dactylus of the 3rd ]>er;vo|ioils. 



