ON TIIK niSTRIRUTION OF THE GENERA. 309 



Antiirctic, Melainphaes gives little light on the special points under con- 

 sideration ; it apparently has closer affinities between its species across the 

 Pacific than acro.-s Central America. 



Trichiwtis : — Pananiic to Lower California, the Caribbean and Gulf to 

 New York and to Montevideo, off Portugal, the Arabian Sea, Buy x)f Bengal, 

 Japan, New Zealand, and Madagascar outline a distribution that may be 

 used in support of both a Panamic and an east Mediterranean strait. The 

 species on the two sides of Central America have very close affinities. 



Chias modus : — The known range of this genus includes the following: 

 south of the Gulf of California, off Pernanibuco in the mid-Atlantic, off 

 northwestern Africa, and in the Bay of Bengal. These are points somewhat 

 favoraljle to the theory of a Central American water way between the two 

 oceans. 



Lophlus: — Retaining Lophiomus in this genus the distribution includes 

 the Panamic and the Cariljbean, Cape Hatteras to Newfoundland, Cape 

 Yerdes to Norway, the Mediterranean, Arabian Gulf, Bay of Bengal, Japan 

 and the Philippines, and off New Guinea and South Africa. The genus 

 does not readily support the idea of a Panamic strait because of the wide 

 differences in the species at opposite sides of the isthmus. 



Chaunax : — Recorded from the Panamic, the Caiibbean and the Gulf to 

 off New York, off northwestern Africa, in the Arabian Gulf, the Bay of 

 Bengal, and off the Fiji Islands. The species on opposite sides of Central 

 America differ radically. Some authors find the same species in both 

 the Atlantic and the western Pacific, an identification that is somewhat 

 questionable. 



Oncocephalus : — Obtained from the Panamic and from the Caribbean and 

 the Gulf of Mexico to Labrador and to Rio de Janeiro. Advocates of the 

 theory of a recent upheaval of the Central American isthmus will hardly 

 find a better instance in their favor, on account of the distribution and the 

 very close relationship of the Panamic to the Caribbean species. 



Dihyauchus : — Inhabits the Panamic region to the Gulf of California, the 

 Caribbean and the Gulf of Mexico to New York, the region off Soudan and 

 the Cape Yerdes, and the Arabian Sea and the Bay of Bengal, As a genus 

 DibranchuR supports the idea of a more or less recent Caribbean strait ; the 

 affinities of the species, however, are but moderately close. 



Malthopsi^ : — Species occur in the Panamic section to the Gulf of 

 California, off the Hawaiian Islands, and in the Bay of Bengal. Not yet 



