216 THE AMERICAN NATURALIST. [Vor. XXXIV. 
a’. Peduncle of second antenne four-jointed. Plate of second joint of 
maxillipeds without hooks. Uropoda with inner angle of peduncle 
the antenna. . . 
Genus Cirolana Leach. 
a. Fifth abdominal segment with lateral angles free, not covered by the 
fourth segment. . . Cirolana linguifrons Richardson, D, surface 
at F3 
P p 
3 
a à € 
Fic. 5.1— a, Mandible of Cirolana borealis ; p, palpus of 
the second pair; 7, first joint; 2, second joint; 72, lobe of the second 
first pair; 7, first joint; /1, lobe of the first joint; 2, second joint ; 
3, third joint. 4, Maxilliped ; z, first joint; e2., epignath ; 2, second 
T joint ; 7?, lobe of the second joint; a, 4, c, d, e; palpus. 
Fic. 4.! — Cirolana 
concharum. 
b. Frontal lamina posteriorly or clypeus anteriorly produced horn- 
like, especially so when seen from the side. 
Cirolana virginiana Richardson, M, 81 fms. 
FK. Frontal lamina and clypeus unarmed, not produced horn-like ; 
anterior margin of the clypeus connected with the frontal 
lamina. 
c. Frontal lamina narrow, elongate, four to six times longer 
than broad. 
d. Extremity of exterior margin of inner branch of the 
uropoda emarginate. 
e. Terminal segment emarginate at its extremity. 
Cirolana concharum (Stimpson), NM, surface to 18 fms. 
Terminal segment not emarginate at its extremity. 
Cirolana impressa Harger, M, 115-321 fms. 
d'. Extremity of exterior margin of inner branch of the 
uropoda not emarginate. 
e. Second pair of antenne long, extending beyond 
the posterior margin of the third thoracic seg- 
ment. Cirolana borealis Lilljeborg, S, 233 fms. 
1 Figures taken from Hansen, 
