MUSEUM OF COMPARATIVE ZOOLOGY. 23 



MACRURA. 



ERYONTID^. 



Pentacheles sculptus. 



Plates III. and IT. 



Polycheles sculptus Smith, Ann. Mag. Nat. Hist., London, 5tli ser.,V. p. 269, April, 

 1880 ; Proc. National Mus., Washington, IL, 1879, p. 345, PI. VIL, 1880. 



Pentacheles spinosus A. M. -Edwards, Bull. Mus. Comp. Zool., VIIL p. 66, De- 

 cember, 1880. 



This species was first described from a single imperfect specimen taken by a 

 Gloucester fisherman, oflf the coast of Nova Scotia, N. Lat. 43° 10', W. Long. 

 61° 20', in 250 fathoms, so that the specimens recorded above, and a large 

 female with eggs, taken, Nov. 16, 1880, off the mouth of Chesapeake Bay, 

 N. Lat. 37° 24', W. Long. 74° 17', 300 fathoms, Station 898j by Lieut. Tanner, 

 on the U. S. Fish Commission Steamer " Fish-Hawk," aflford an opportunity for 

 a more complete description than that originally given. 



The sides of the carapax are nearly parallel posteriorly, but arcuately con- 

 vergent anteriorly, and the greatest breadth i^ just in front of the cervical 

 suture, and is about three fourths of the length along the median line. As 

 seen from above, the anterior margin is concave in outline, so that the acute 

 and spiniform lateral angles are much in advance of the rostrum, which is 

 armed with two spines close together and projecting obliquely upward and 

 forward. About a third of the space between the median line and the lateral 

 angle each side is occupied by a very deep orbital sinus nearly parallel with the 

 lateral margin, considerably deeper than broad, somewhat narrowed and evenly 

 rounded posteriorly, and completely filled by the large ophthalmic lobe. On 

 the inner side of this sinus the frontal margin projects in a small spiniform 

 tooth, but outside the margin is unarmed and curves regularly to the lateral 

 angle. Just behind the orbital sinus there is a smooth and evenly cur\'ed 

 depression in the surface of the carapax exposing a small area on the posterior 

 part of the ophthalmic lobe, more fully described beyond. The cerv'ical suture 

 di\ddes the dorsal surface of the carapax into two pretty nearly equal portions, 

 and is deep and conspicuous, but is indicated in the lateral margin, each side, 

 by a slight emargination only, which is scarcely deeper than the emargination 

 between the anterior and posterior lobes of the hepatic region. The lateral 

 margin is armed, on the anterior lobe of the hepatic region, with (including the 

 anterior angle) six, or rarely only five, small and slender spiniform teeth di- 



