50 Benedict — Arcturidtc in the U. S. National Museum. 



The second joint is about as broad as long and is armed with three short 

 spines ; the third joint is armed with two spines pointing outward and 

 upward; the fourth and fifth joints are long and slender, unarmed; the 

 flagellum has but three joints. The first thoracic segment, as in hystrix, 

 lias a transverse row of eight spines; the thin sides of the segment ex- 

 tend forward under the head ; the second and third segments also have 

 eight spines arranged as in the first. The fourth segment is so constricted 

 in the middle as to give it the appearance of two segments anchylosed ; 

 this segment has a double row of eight spines ; between the two median 

 spines of the posterior row and the constriction are two additional spines; 

 these spines are smaller than those of the median rows, taking the ar- 

 rangement longitudinally. The fifth, sixth, and seventh segments have 

 spines regularly placed on each side of the median line; next farther 

 down on the segment are two spines longitudinally placed ; next, on the 

 margin, are three spines united at the base, the middle one largest. The 

 first abdominal segment is very short, with a transverse row of six spines ; 

 on the second segment spines are placed on the two median lines only ; 

 these are doubled and crowded. On the terminal segment there are two 

 rows of small spines regularly placed on one specimen and disarranged 

 on the other. The abdomen is terminated by two blunt divergent spines. 

 The specimens are sparsely set with short, stiff hair. All of the legs are 

 armed with a single spine on the basal joint. 



This species can readily be distinguished from hystrix by the median 

 spine of the head, by the extra pair of spines on the fourth segment of 

 the thorax, by the armature of the antennae, and by the arrangement of 

 the spines on the abdomen. 



As Professor Sars suggests, hystrix may be made the type of a new 

 genus; it will then be necessary to place this species with it. (No. 7915, 

 U. S. N. M.) 



Astacilla granulata (G. 0. Sars). 



Leachia granulata G. O. Sars, Arch. Math. Nat.. II, p. 351, 1S77. 

 Astacilla <<iitn-ic<tn<i Harger, Am. Journ. Sei., (.'J) XV, p. 374, 1878. 

 Astacilla granulata Harger, Proc. IT. S. Nat, Mus., II, p. 161, 1N7!>. 

 Astacilla granulata Sars, Nor. N. Atlan. Expd., Crust., p. 1(17, pi. ix. fi^s. 

 27-35, 1885. 



One specimen from the Gloucester fishermen, Grand Banks. 

 Astacilla diomedeae sp. nov. 



The head is excavated in front, nearly rectangular, a little broader be- 

 hind than in front, The eyes are but little swollen, are round, and are 

 situated a little anterior to the middle of the margin. 



The antennas are closely like those of Astacilla nodosa (Dana). 



The first segment of the thorax has the same width as the head ; the 

 second and third segments are successively wider and also shorter than 

 the first ; the fourth segment is very wide at the anterior end, as in 

 nodosa ; like the latter, it tapers gradually backward to the fifth segment. 

 The segments posterior to the fourth are longer than the first three and 

 are successivelv narrower. 



