72 



emarginate, not covering the posterior. part of the cephalothorax. Eyes very large, eye-stalks 

 moderately long. Antennulae with the first joint of the peduncle slightly longer than the sum 

 of the two next joints; male lobe as long as the third peduncular joint. Antennal squama 

 lanceolate with a distal transverse suture, and setae along both margins. Labrum obtuse in front. 

 Left mandible (figs. 2C and 2 el) has the incisive part strongly produced with a number of obtuse 

 teeth of various size, the movable lacinia broad, the setae extremely small and no vestige of 

 a molar tubercle; right mandible almost as the left; the palp with the second joint considerably 

 curved, somewhat broad and distally tapering, third joint a little more than half as long as 

 the second. Maxillae (fig. 2e) nearly as in Mysideis insignisQ. O. S. ; the exopod unusually small. 

 Maxillipeds (fig. 2/) have the endopod very broad as in Mysideis, but with a small number 

 of setae along the inner margin-, the proximal joints without any perceptible lobe; claw strong; 

 exopod present (not drawn). The gnathopods (fig. 2g) differ widely from those in Mysideis; 

 they are much more slender than the maxillipeds and only a little stronger than the thoracic 

 legs; the claw is strong and very long. The thoracic legs (fig. 2/1) moderately slender; sixth 

 joint divided into three subjoints by two vertical articulations; seventh joint and the claw claw- 

 shaped and extremely long. The marsupium seems to be formed by two pairs of lamellae. 



Pleopods in the female nearly as in Mysideis insignis G. O. S. Pleopods in the male 

 essentially as in Lcptomysis gracilis G. O. S. ; endopod of first pair unjointed, short, with the 

 usual lateral plate (fig. 2 i) • exopods of second, third and fifth pairs a little longer than the 

 endopods but without modified equipment; exopod of fourth pair somewhat longer than the 

 endopod, with a strong spine and a thick seta on the outer side respectively of the antepenul- 

 timate and the penultimate joint (fig. 2 k). Uropods somewhat slender, with long setae along 

 both margins of both rami (fig. 2/); exopod somewhat longer than the endopod, without spines, 

 while the endopod has spiniform processes, some among them very long, from the lower side 

 along the inner margin (figs. 2 m and 2 n). Telson (figs. 2 m and 2 ;/) essentially as in Mysidetes, 

 much shorter than the endopod of the uropods, tapering nearly from the base, with lateral 

 spines and posteriorly a deep incision. 



Remarks. — As already mentioned, this new genus agrees with Mysideis in some, with 

 Lcptomysis in other, features, while the telson is about as in Mysidetes. But the mandibles differ 

 strongly from those in these genera, and the armature of the endopod of the uropods is unique. 



42. Uromysis ariuata n. sp. PI. XI, figs. 2a — 211. 



Stat. 109. July 5/6. Anchorage off Pulu Tongkil, Sulu-Aichipelago. 13 m. Plankton. 15 specimens 

 (most of them immature). 



Description. - - Body slender. Frontal plate (figs. 2a — 2Ó) triangular, a little more than 

 twice as broad as long, with the end subacute and the oblique margins nearly straight. Eyes 

 very large, dark brown ; the distal joint of the eye-stalks somewhat broader than long, increasing 

 in breadth from the base to the end, which is as broad as the cornea. Antennal squama 

 reaching conspicuously beyond the end of the antennular peduncle, very oblong-lanceolate, about 

 seven times as long as broad; the joint beyond the transverse suture about, or slightly more 

 than, twice as long as broad. 



