no. lT.-.s. oy MARINE COPEPODA IND CLADOCERA. SHARPE. 427 



B 22. Body cylindrical, no conspicuous constrictions between the segments. Nata- 

 tory legs normal, but inner rami of first Legs two- in three-segmented. Inner 

 rami in third legs modified in male. One egg sac Brackish pools and 



ditches YIesochra. 



Body abnormal, with decided constrictions between its segments. Natatory 



legs bent, elbow-like. LO to 30 fathoms Laophontodes female). 



B 23. First antenna four- to five-segmented, stout. Furca lamellar. Both segments 

 of fifth feel especially narrow. 6 to 10 fathoms, muddy bottoms. 



Laophontopsis. 



First antenna of seven segments B 24. 



B 24. Inner ramus of first leg much longer than the outer. Fifth legs not foliaceous, 



but rather narrow. Furcanormal. Bottom forms, pelagic Vormanella. 



Inner ramus of first leg shorter than the outer, with an odd rod-like projection 

 from its basal segment. Fifth legs foliaceous. Furca with a lame thick ter- 

 minal spine, and a few set.-e. Bottom washings, pelagic. . < 'eylonia I female). 



B 25. Anterior antenna four- to six-segmented. One egg sac Marine B.26. 



Anterior antenna seven- to eight-segmented. < Ine egg sac Fresh-water. . B 27. 

 B 26. Basal segment of fifth foot a broad plate Terminal segment comparatively 



short and broad. Pelagic, sandy bottom Enhydrosoma (female). 



Basal segmenl of fifth foot narrow and produced into a narrow flange. Terminal 



segment of same very long and narrow. Pelagic, muddy sand Cletodes. 



B 27. Anterior antenna eight-segmented, the terminal part of four segments. Inner 

 rami of first legs two- or three-segmented. Littoral and bottom. 



Attheyella (female). 

 Anterior antenna seven-segmented, the terminal part of three segments. Inner 



rami of first logs always two-segmented. Bottom Moraria. 



A. Inner ramus first leg one-segmented \ I 



Inner ramus first leg two- or three-segmented \ (i. 



A 1. Outer ramus of first leg three-segmented, strongly spined V 2. 



Outer ramus of first leg one-segmented \ 3. 



A 2. Fifth loirs very minute, plate-like, and lobed on distal margin. First antennae 

 five-segmented; basal segments much dilated. Body tumid and gibbous. 



hitt oral. 5 to 20 fathoms. Algae Tlyopsyllus. 



A 3. Outer rami of the second, third, and fourth legs three-segmented \ 1. 



Outer rami of the second, third, and fourth legs two-segmented A •">. 



A 4. First legs imperfectly prehensile. Fifth foot of male one-segmented; of female, 

 two-segmented. No true ovisac Head and last thoracic segment very 



large, produced ventrally. 3 to 30 fathoms. Sandy bottom Tegastes. 



A 5. First legs not prehensile. Otherwise much as Tegastes Parategastes. 



A G. Inner ramus of first legs two-segmented V 7. 



Inner ramus of first legs three-segmented A 24. 



A 7. Outer rami of first legs two-segmented. One egg sac \ 8. 



' >uter rami of first legs t hree-segmented \ LO 



A 8. Fifth legs two-segmented; first legs prehensile A 9. 



Fifth legs one-segmented; first legs not pr< hensile; inner rami peculiarly bent at 

 right angles, and with natatory seta'. One egg sac. Pelagic, in towings. 



Euterpt . 

 A 9. Outerrami of firsl Legs shorter than the inner. Body not flattened. First antenna 



eight-segmented. Tidal pools, or "tidal lagoons" Pseudothalestrh. 



Outer rami of first legs Longer than the inner. Body flattened, broad, bit total, 



amongst algae and in tidal pools, or lagoons Zaus (mostl) i. 



A 10. Rami of first legs enormously broadened, flattened, and otherwise modified. 

 Body short and flat. Funa lamellate, with rudimentary seta'. Fifth legs 



two-segmented. Littoral, on Laminaria, etc Porcellidium. 



Rami of first legs not unusually modified or de\ eloped A 11. 



