COPEPODS OF THE WOODS HOLE REGION 561 



2. Rami of first legs 2-segmented, endopod longer than exopod; 



second, third, and fourth exopods enlarged, with stout 

 spines; exopod of second antenna 1-segmented; littoral, among 

 algae cf 9 Platychelipus Brady, 1880 



Rami of first legs 3-segmented, of second legs 2-segmented, of 

 third and fourth legs entirely lacking; fifth legs 1-segmented; 

 each caudal ramus with 1 apical spine; parasitic on octopus. 



9 Cholidya Farran, 1914 



Rami of first legs not segmented alike 3 



3. Exopods of first legs 3-segmented, endopods 2-segmented; body 



segments with posterior spines; basipods not geniculate; third 

 and fourth endopods lacking; in brackish pools- _ 9 Nannopus Brady, 1880 

 Exopods of first legs 3-segmented, endopods 1-segmented; basi- 

 pods all geniculate; 2 rows of dorsal spines; lateral spines on 

 the head and first segment; muddy bottom, in algae. 



9 Echinopsyllus G. O. Sars, 1909 



4. Endopods of second and third legs entirely lacking; second 



exopod 1-segmented, third exopod 2-segmented; fifth legs 

 foliaceous, 2 segmented, reduced in the male; bottom plankton. 



cT 9 Laophontina Norman and Scott, 1905 



Endopod of third legs 1-segmented, rudimentary 5 



Endopod of third legs with 2 or more segments 16 



5. First legs natatory, with setae but without terminal claws 6 



First legs prehensile, armed with terminal claws 13 



6. Endopods of first legs 2-segmented 7 



Endopods of first legs 1-segmented 11 



7. Exopods of first legs 2-segmented, as long as endopods; 2 rows 



of latero-dorsal pectinate processes; fifth legs without a basal 



expansion; muddy bottom, 12 fathoms-- 9 Ceratonotus G. O. Sars, 1909 



Exopods of first legs 3-segmented, the same length as the endo- 

 pods; no pectinate processes; fifth legs with basal expansion 

 bearing 4 setae; littoral, Banyuls 9 Tryphoema Monard, 1926 



Exopods of first legs 3-segmented, usually not same length as en- 

 dopods -- 8 



8. Endopods of first legs longer than exopods; second, third, and 



fourth endopods 1-segmented, with a single spine; segments of 

 fifth legs fused, with 10 setae; littoral, 6 to 20 fathoms. 



cf 9 Pontopolites T. Scott, 1894 

 Endopods of first legs shorter than exopods 9 



9. Exopods of third legs 2-segmented; fifth legs tipped with 3 spines 



and a spatulate process; exopod of second antenna 1-seg- 

 mented, and very short; fresh water, shallows. 



9 Parastenocaris Kessler, 1913 (p. 289) 

 Exopods of third legs 3-segmented; fifth legs with setae only 10 



10. Endopods of second legs 2-segmented, of third and fourth legs 



2- or 1-segmented; caudal rami widely separated; no legs 

 modified in male; 2 ovisacs; muddy bottoms, 30 to 40 fathoms. 



c? 9 Eurycletodes (part) G. O. Sars, 1909 

 Endopods of second, third, and fourth legs in female 1-seg- 

 mented, in male, second 1-segmented, third 2-segmented, 

 fourth 3-segmented, the latter with a 3-barbed apical spine; 

 brackish pools 0^9 Itunella Brady, 1894 



