THB FOSSIL STALK-EYED CRUSTACEA 89 



Relation. — The genus Graptocarcinus ^' was described from a 

 species^® in the upper Cretaceous of Texas. Our species has a 

 greater fronto-orbital distance, due to the larger orbits, and the 

 carapace begins to widen at a greater distance from the orbits. 



Sub tribe Gymnopleura Bourne 

 Family RANINIDAE Dana 



Anterior thoracic sterna broad, posterior thoracic sterna narrow 

 and keel-like; posterior thoracic epimera largely exposed by reduc- 

 tion of branchiostegite ; female openings on coxae; last pair of 

 pereiopods dorsal in position, normal or reduced in size; sternal 

 canal present; thoracic nerve ganglion-chain elongate; antennary 

 sternum triangular spout-shaped; branchiae eight on each side 

 (Bourne). 



This family is represented in British Columbia, Washington, 

 Oregon, and California by 12 species distributed in five genera. It 

 is altogether absent to-day from the adjacent waters of the Pacific 

 although occurring further south, from Mexico to Panama. 



KEV TO THB FOSSIL GENEKA OF THE FAMILY RANINIDAB ON THB PACIFIC SLOPE OF NORTH 



AMERICA 



A\ Carapace of moderate convexity, not e.srj^-shaped. 



B\ Sternum very narrow, or linear, between feet of second to fifth pairs. 

 Carapace very broad in proportion to its length ; anterior margin also 



very broad, with several strong teeth Ranina, p. 89. 



B". Sternum broad between feet of first and second pairs. 



C\ Sternum very narrow between feet of third to fifth pairs. Anterior 



margin of carapace nari'ow, with three teeth Ranidina, p. 99. 



C". Sternum broad between feet of third pair. Fronto-orbital border 

 broad. 

 D\ Sternum linear between feet of fourth and fifth pairs. Width 

 of carapace about half its length. Rostrum simple. 



Raninoides p. 92. 



D^ Sternum gradually diminishing in width from first to fifth 



sternite. Width of carapace about two-thirds or three-fourths 



of its length. Rostrum bifid Palaeocorystes, p. 101. 



A". Carapace extremely convex, resembling half an egg ; a prominent midrib ; 

 one strong antero-lateral spine Eumorphocorystes, p. 100. 



Genus RANINA Lamarck 



Ranina Lamakck, Sys. Anim. sans Vert., 1801, p. 156; type, R. ranina 

 (Linnaeus). 



Sternal plastron linear between bases of feet of second pair. 

 Second article of outer antennae bearing on outer border a large 

 auriculiform prolongation. Anterior border of carapace very wide, 



2° Roemer, Ncue.s Jabrb. f. Mineral., Geol. u. Palaeont., 1887, vol. 1, Stuttgart, p. 173. 

 ^ G. texanus Roemer, Idem, text-figs. «, h. 



3020—26 7 



