259 



Fliudcrsi, Ihndcrsoni, incisiis, Lowisii, oblujnus, plcbs, sabsechoia and victoriensis. The depth 

 at whicli the same species occurs, varies also often considerably, Pont. Challe7igcri, for instance, 

 was trawled at iioo, but also at 2150 fathoms, Pont, occidentalis at 978 and at 2232, Pont, 

 echinulatns at 43 and 480. 



Key to the species of the genus Pontophilns Leach. 



«, Outer margin of antennal scale not denticulated. 



(5j First four abdominal somites dorsally smooth. 



fj Three spines on mid-dorsal line of carapace. 



d^ Carapace with four lateral spines, which, like the three of 



the mid-dorsal line, are not the acute endings of carinae. 



Rostrum with the lateral margins unarmed and tapering 



to a narrow rounded apex pilosns Kemp 



(Stanley Kemp, Records Indian Museum, Calcutta, Vol. XII, Part VIII, 

 1916, p. 367, PI. VIII, fig. 4.) 



d,_ Carapace with two lateral keels, the upper with two spines, 



the lower with one. 



e^ Rostrum long and narrow, projecting beyond the line of 



the spiniform outer angles of the orbits, terminating in 



an acute point and armed about in the middle with a 



pair of small lateral spinules norvegicus (M. Sars) 



(Stanley Kemt, The Decapoda Natantia of the Coasts oflreland, Dublin 

 1910, p. 162, PI. XXI, figs. 9, a and b.) 



e„ Rostrum very short, tridentate, the median tooth scarcely 



broader and very little longer than the lateral, not 



projecting beyond the line of the spiniform outer angles 



of the orbits brevirostris S. I. Smith 



(S. I. Smith, Bull. AIus. Comp. Zoology, Cambridge, Vol. X, N" i, 1882, 

 p. 35, PI. VII, figs. \ — \Ik) 



d.^ Carapace with two lateral spines. 



^j Peraeopods of the first pair with the outer margin of the 



merus unarmed. 



Rostrum with two pairs of lateral teeth. 



/j Eyes small, the length of carapace, including the rostrum, 



beinof about ten times as long as their greatest diameter abvssi S. I. Smith 

 (S. I. Smith, Annual Report Commiss. of Fish and Fisheries for 1882. 

 Wash. 1884, p. 363 (19); idem for 1885, Wash. 1886, PI. XI, fig.s. 3, 3^.) 



/, Eyes large, the length of carapace, including the rostrum, 



being 5,1 — 5,8-times as long as their greatest diameter. 



g^ Species 73 mm. long. Abdomen 2Y„-times as long as 



carapace. Anterior gastric spine as large as posterior occidentalis Faxon 

 (W. Faxon, in: Memoirs Museum Comp. Zoology, Cambridge, Vol. XVIII, 

 1895, p. 131. PI. D, fig. 2- 2d.) 



