MARINE ISOPODA OF NEW ENGLAND, ETC. 333 



of its superior surface ; tliird segment longer and more slender than the 

 second ; flagellum of more than twenty articulations, which become in- 

 distinct near the base, and are furnished with terminal setae. AntennsB 

 about thrice the length of the body in the female, somewhat shorter 

 in the male, the sexes differing in the fourth and fifth segments, which, 

 in the females, are subequal in length and, together, as long as the body, 

 while in the male the fifth is shorter than the fourth, and the two seg- 

 ments together are about two-thirds as long as the body. The flagel- 

 lum is long, slender, and multiarticulate. Maxillipeds (pi. Ill, fig. 15 b) 

 with the external lamella sub-rhombic, emarginate on the exterior distal 

 side j palpus five-jointed, first segment short, produced externally into a 

 very acute angle ; second and third segments broad and flattened ; fourth 

 narrow with the inner angle produced and rounded ; fifth short, ovaL 

 Maxillae of the ordinary form, outer pair with slender lobes. Mandibu- 

 lar palpus elongated, last segment strongly curved. 



Thorax widest at the fourth segment; first four segments forming 

 about one-third its length on the median line, last segment longest, all 

 with their anterolateral angles produced, the anterior four with the 

 epimera projecting as an acute process below, and in front of, the angle. 

 First pair of legs (pi. Ill, fig. 15 d and d') about three-fourths the length of 

 the body; dactylus short; propodus shorter than the carpus; slightly 

 hairy, especially on the propodus with slender hairs. Kext three pairs of 

 legs longer than the body, subequal, but increasing a little in length to the 

 fourth; dactyli slender and acicular ; propodi and carpi subequal, spinu- 

 lose along their inner margins in the second pair, but not in the third and 

 fourth. Last three pairs of legs with the carpus strongly dilated and 

 flattened, subcircular as seen in pi. Ill, fig. 15/, where the sixth pair is 

 represented; propodus also much flattened and dilated; both segment* 

 strongly ciliated with plumose bristles, as is also the ischium, or second 

 segment along the outer dilated margin ; dactylus about half the length- 

 of the propodus instead of less than one-third its length, as in U. cornuta 

 G. O. Sars, the species most resembling the present. 



Pleon much broader than long, broadly rounded behind. Operculum 

 also broader than long, strongly roof-shaped. Uropods (pi. Ill, fig. 15 g) 

 ■with the basal segment shorter than the rami, which are uniarticulate, 

 cylindrical, of equal length, obtuse and tipped with a coronet of short 

 spines. The inner ramus is more robust, but not longer than, the outer. 



Color in alcohol, honey yellow ; length 4.5'»°» ; breadth 2.2™™. 



This species appears to approach U. cornuta G. O. Sars,* but may 

 be readily distinguished by its greater size, by the shortness of the 

 rostrum, the equal rami of the uropods, and the shape of the external 

 lamella of the maxillipeds, which he describes in that species as "ver- 

 sus apicem dilatata et emarginata utrinque acute producta." In the 

 third and fourth pairs of legs, moreover, the carpus and propodus are 

 not armed with spines as in that species according to Sars' description. 



• Chr. Vid. Selsk. Forli., 18G3. p. 209, 1864. 



