LITTORAL FAUNA OF THE PANAMA PROVINCE. 237 



J'acific Coast. Atlantic Coast. 



XT 1 • { Hypoconcha sabnlosa. 



Hypocouclia ijaiiamensis. { 



( ai'cuata. 



Lepidopa myops. Lepidopa scutellata. 



Glibanarius pauamensis. Clibauarius vittatus. 



T, . . , . . I Paguristes depressus. 



Pagunstes degueti. - { ,, ■ 



( senceus. 



Paguristes fecundus. Paguristes lymani. 



Pylopagurus longimauus. ) 



affinis. \ Pylopagurus ungulatiis. 



" hirtimanus. " rosaceus. 



Spiropagurus occideutalis. Spiropagurus iris. 



Petrolisthes occideutalis. Petrolisthes sexspiuosus. 



Sicyouia affinis. Sicyouia edvvardsii. 



Lysiosquilla desaussurei. Lysiosquilla scabricauda. 

 Squilla panaiueusis. ) 



" biformis. \ Squilla intermedia. 



But few characteristically Indo-Pacific genera are found in the Panamian 

 Province. An jS^thra from the western coast of Mexico has been described 

 by S. I. Smith as a new species by the name of ^. scutata, but A. Milne 

 Edwards regards it as a mere variety of the Indo-Pacific ^. scrupoaa. Daira 

 americana Stimps., a species closely related to the Indo-Pacific D. perlata 

 (Herbst), inhabits the western coast of Central America and Mexico. Four 

 species of Trapezia and one species of Quadrella have also been found on the 

 same coast.* Of the two known species of Chonlihinia, one comes from North- 

 ern Australia and New Guinea, the other from the Gulf of California. One 

 species of Carp'dodes (C. einctimanus), a genus rather characteristic of the 

 Indo-Pacific region, is recorded from Cape St. Lucas.f Still, the number of 

 peculiarly Indo-Pacific genera is so small as barely to give a perceptible tinge 

 to the Panamian fauna. The great sea-distances separating the tropical Indo- 

 Pacific Province from the Panamian, together with the adverse equatorial 

 current which sets against the richer fauna of the East, have allowed a 

 marked differentiation to come about between these two provinces of the 

 great Tropical Realm. On the other hand, the small num])er of genera 

 peculiar to the Panama fauna, and the large numlier, not only of West In- 



* Trapezia rufopunctata (Herbst), an Indo-Pacific species, recorded from tlic island of Socorro ; 

 T. cymoioce (Herbst), also an Indo-Pacific species, from Panama and Acapidco ; T. formosa Smitb, from 

 Panama; T. nigrofusca Stimps., from Cape St. Lucas; Quadrella nitida Smitli, from Panama. Two species 

 of the eastern genus Myra, from tlie Gulf of California, have been recently described by Miss M. J. Ilatlibun 

 (Proc. U. S. Nat. Mus., XVI. 2.')5, 250, 1893). But this genus is hardly separable from the American 

 genus Persephona. 



f Remipes testiulinarius, although it belongs to a. ffeniis of circumterraneau distribution, belongs in the 

 category ni speries which have reached the west shore of tro])ical America from tlie Indo-Pacific region. 



