242 



STALK-EYED CRUSTACEA. 



An analysis of tins list discloses the enormous — often cosmopolitan 

 distribution of deep-sea types and their lack of special affinity with the 

 nearest littoral fauna. Only four new genera were found among the Stalk- 

 eyed Crustacea taken at a greater depth than 500 fathoms, viz. Tracliycar- 

 cimis, CalastaciiSy Scolophthalmus , and Ceratomysis. Of these, Tr achy car cinus 

 (a Corystoid crab from 546-695 fathoms) is represented in deep water in the 

 Caribbean Sea by an undescribed species which is probably congeneric, and 

 by Tricliopeltarion (151 fathoms). Both of these genera are closely related 

 to, and perhaps derived from, Ilypopeltarium^ a shallow water form foimd on 

 the shore of South America from La Plata around Patagonia to Chile. Galas- 

 taciis is allied to Calocaris of the North Atlantic, 150-400 fathoms. Scolopli- 

 thalmits, a deep-sea Scliizopod, is probably a near relative of Ilansenomysis 

 from off the west coast of Greenland, and it is worthy of note that both 

 Scolophthalmus and Ceratomysis confess by their structure their kinship with 

 Boreomysis, a genus which reaches its highest development near the arctic 

 and antarctic regions. 



Iconaxius has been previously known from remote parts of the Pacific, 

 near the Celebes and Kermadec Islands. The only other known species of 

 Paracrangon inhabits Puget Sound and the seas near Japan. Sclerocrangon is 

 without doubt a genus of boreal origin. It is represented in high northern 

 latitudes by circurapolar littoral species, and on both sides of the Atlantic by 

 deep-water species that range as far south as 3P 57' N. (S. agassizii). One 

 of the " Albatross " west coast species, S. procax^ extends the range of this 

 genus southward in deep water to within 4° 3' of the equator (Station 3380, 

 899 fathoms, bottom temperature 37° P.). The genus Pandalopsis is repre- 

 sented in the ^'Albatross" collection by the same species that was discovered 

 by the " Challenger" off Monte Video. P eialopWiahmis was known, prior to 

 the " Albatross " Expedition, only through the unique specimen obtained by 

 the "Challenger" Expedition from a great depth in the tropical Atlantic. 

 Like Scoloplithalmus and Ceratomysis, it is related to Boreomysis, All the 

 other genera included in the above list may be said to have a world-wide 



■ J 



distribution. 



That the truly deep-sea Crustacean fauna of the Panama region has no 

 special aflinity with the littoral fauna of the same region may perhaps be 

 more clearly shown by placing in two columns the distribution of the 

 Panamian species found below 500 fathoms, or the habitat of representative 

 species, when such are known. 



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