518 THE AMERICAN NATURALIST. | [Vor. XXXIV. 
Key to Species. 
A. A narrow bridge between two cavities connects the cardiac and 
branchial regions. . . L. pontifera Stimpson, M( CH) 
A’. No bridge connects the inus idi branchial regions. 
Fic. 14. R dallia ornata 
B. A transverse ridge between the large branchial protuberance and 
the lateral margin . L. cariosa Stimpson, 47(CH)G 
B’. A small circular ciugiberance beiden the large branchial protu- 
berance and the lateral margin . JZ. cadaverosa Stimpson, G 
Genus Iliacantha Stimpson . . . . J: subglobosa Stimpson, M( CH)G 
Genus Myropsis Stimpson . . . . . M. guinguespinosa Stimpson, G 
KEY TO THE GENERA OF THE FAMILY DORIPPID;E. 
A. The external coer ech leave all the anterior part of the buccal 
cavern uncovered M CX as eee 
A’, The external madio cover ‘the buccal « cavern . . Cyclodorippe 
Fic. 15. — Ethusa mascarone. 
THE SPECIES OF DORIPPID&. 
Genus Ethusa Roux. 
Key to Species. 
A. Eyestalks Pint extending laterally beyond the postorbital spine 
E. mascarone americana (A. Milne-Edwards), M (CH )G 
A’, Eyestalks short, directed forward. 
