PROCEEDINGS OF UNITED STATES NATIONAL MUSEUM. t 



of the first aud second combined. The structure of the first and second 

 pairs of thoracic feet simihir to those of P. atlantica. The spine on the 

 posterior extremity of the basal joint of the third and fourth pairs is 

 wanting- in the present species, and in its place is a bristle-like hair. 

 The fifth pair of legs are relatively shorter, when compared with those 

 of aUanilca ; a prominent spine on the posterior extreuiity of tlie basal 

 joint, but none on the following joint, in front; the third joint short, 

 broad, and considerably arched above; the fourtli joint (palm) broadly 

 quadrate, almost as broad as long, the superior border rounded pos- 

 teriorly to the articulation of the third joint, the lower border slightly 

 curved, the character of the dentition on the anterior border si!)iilar to 

 that of atlantica in the general arrangement of the teeth, but the teeth 

 are not nearly so prominent, or pointed, the lower, single tooth but 

 slightly separated from the larger crenulated tubercle; the prolonged 

 inferior angle more curved upward, and shorter than in the former spe- 

 cies. The fifth joint curved, about as long as the anterior margin of 

 the palm, a low convexity on the inferior margin. The first ])air of 

 caudal appendages do not reach as far backward as the third pair, ex- 

 tending to, or slightly beyond, the middle of the rami of the last pair; 

 the second pair extends to, or slightly beyond, the point of articulation 

 of the rami of the third jiair, and more than half way the length of the 

 branches of the first pair. 



The characters of the fifth, or prehensile pair of legs, and the rela 

 tive length of the second pair of caudal ai>pendages are sui^eient to 

 readily distinguish this species from P. atlantica. 



In the young of S'""" the shape of the hand is the same as in the 

 adult. On the anterior margin there are, in the place of the den- 

 tated tubercle, two or three pointed teeth, springing from a slightly 

 elevated base. The hand of the male is similar to that of the female, 

 except that the immovable finger rises from a more receding angle, 

 which, however, is less receding than that observed in P. atlantica. 



Clans confuses this species with P. sedentaria. ( Vide Zeitschrift wis- 

 sen. Zoologie, Leipzig, 1872, xxii, pis. xxvi, xxvii, fig. 1-12.) 



The number of specimens examined was ten — nine females and one 

 male. Their lengths varied from 3 to 12"'™. 



Locality. — Pacific Ocean, north and south of the equator — from lat 

 itude 40° north to 30^ 42' south; and from longitude 97° 14' west to 

 157° 37' west. The temperature of the water of the localities whence 

 the specimens were obtained varied from GG° to 73° Fahr. 



The following facts may be deduced by comparison with P. atlantica. 

 The present species is smaller in size, less numeroxis in the localities 

 given, and a relatively larger i)roi)ortion of those in the collection came 

 from localities south of the equator. 



Pheonimella, Clans. 



The shape of the head and antennre, and the general foi^n of the 

 thorax and abdomen very similar to Phronima. The third pair of 



