28 PROCEEDINGS OF THE NATIONAL MUSEUM. vol.xxxi. 



c. Two epimeral s])ines on each side of anterior section of sixth abdominal seg- 

 ment. Upper lateral keel of carapace present. Antenna! spine obsolete. 

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

 margin of antennal scale projecting considerably beyond terminal lobe, 



serrated on both margins longispina 



C / . One epimeral spine on each side of anterior section of sixth abdominal seg- 

 ment. Antennal spine more or less distinct. Branchiostegal lobe 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 dorsal ly slightly keeled, with small, posteriorly 

 projecting spines. Epirnera of five anterior abdominal segments pointed 

 posteriorly. Branchiostegal lobe rounded. 

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



Branchiostegal lobes moderately developed zoea 



f. Carapace suddenly constricted anteriorly, forming a distinct shoulder 

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

 ostegal lobe greatly expanded scapularis 



e / . Abdominal segments dòrsally not keeled, without spines. Kpimera of 

 five anterior abdominal segments rounded posteriorly. Branchiostegal 



lobe slightly angular affinh 



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. Epirnera 

 of five anterior abdominal segments ending in small points posteri- 

 orly elegans 



3. GNATHOPHAUSIA INGENS (Dohrn). 



Lophogaster ingens Dohrn, Zeitschr. wiss. Zool., XX, 1870, p. (HO, pi. xxxi, figs. 

 12-14. 



Gnathophausia, ingens (i. 0. Saks, Forh. Selsk. Christiania, 1883, No. 3; Rep. Chal- 

 lenger, XIII, 1885, j). 30, pi. 11. 



I have never soon this species. It is founded upon a very 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 

 strongly incline to the opinion that it will prove to be G. calcarata, 

 representing an old female of that species, in which ease it will be 

 called G. ingens, the name calcaraia becoming a synonym. 



G. ingens especially agrees with G. calcarata in the following 

 important characters: 



(1) General form of body, and arrangement of keels and spines of 

 carapace. 



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

 of the tive anterior segments are identical in both forms. 



(8) Shape of antennal scale. 



It differs from G. calcarata in the following respects: 



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



of the carapace, the supraorbital spine being even wanting, the branchi- 



ostegal spine being obsolete. 



