28 PROCEEDINGS OF THE NATIONAL MUSEUM. vol. xxxi. 



c. Two epimeral spines on each side of anterior section of sixth abdominal seg- 

 ment. Upper lateral keel of carapace present. Antennal spine obsolete. 

 Branch iostegal lobe with a well-marked, triangular spine. Spine of outer 

 margin of antennal scale projecting considerably beyond terminal lobe, 



serrated on both margins longisjyina 



c'. One epimeral spine on each side of anterior section of sixth abdominal seg- 

 ment. Antennal spine more or less distinct. Branchiostegal lube without 

 spine, generally rounded, rarely angular. Spine of outer margin of anten- 

 nal scale not, or only slightly, projecting beyond terminal lobe. 

 d. Upper lateral keel of carapace present. 



e. Abdominal segments dorsally slightly keeled, with small, posteriorly 

 projecting spines. Epimera of fiveanteriorabdoniinalsegments pointed 

 posteriorly. Branchiostegal lobe rounded. 

 /. Carapace not suddenly constricted anteriorly, and forming no shoulder. 



Branchiostegal lobes moderately developed 20m 



j' . Carapace suddenly constricted anteriorly, forming a distinct shoulder 

 in front of the anterior ends of the upper lateral keels. Branchi- 

 ostegal lobe greatlj' expanded scapuktris 



e'. Abdominal segments dorsally not keeled, without spines. Epimera of 

 five anterior abdominal segments rounded posteriorly. Branchiostegal 



lobe slightly angular ajfin>s 



d^. Upper lateral keel of carapace wanting. Branchiostegal lobe rounded or 

 angular, but without spine. Abdominal segments dorsally without keel, 

 but posteriorly with a small, depressed, triangular projection. Epimera 

 of five anterior abdominal segments ending in small points posteri- 

 orly elegans 



3. GNATHOPHAUSIA INGENS (Dohrn). 



Lophogaster imjenx Dohrn, Zeitschr. wiss. Zool., XX, 1870, p. 610, pi. xxxi, figs. 

 12-14. 



Gnathophausia ingensG. O. Sars, Forh. Selsk. Christiania, 188.3, No. 3; Eej). Chal- 

 lenger, XIII, 1885, p. 30, pi. II. 



I have never seen this species. It is founded upon ti veiy old 

 female, sexually" mature, and a similar female has served as the basis 

 for Sars's description. It is very closely allied to G. calcarata., and 1 

 strong-l}^ incline to tiie opinion that it will prove to be G. calcarata^ 

 representing an old female of that species, in Avhich case it will be 

 called G. ingen^., the name calcaraia becoming' a synonym. 



G. ingens especiallj^ agrees with G. calcarata in the following 

 important characters: 



(1) General form of ])ody, and arrangement of keels and spines of 

 carapace. 



(2) Sculpture and armature of abdomen, especially as the epimera 

 of the live anterior segments are identical in both forms. 



(3) Shape of antennal scale. 



It differs from G. calcarata in the following respects: 

 (1) In the shorter rostrum and the inferior development of all spines 

 of the carapace, the supraorl)itaI spine being even wanting, the branchi- 

 ostegal spine being obsolete. 



