BATHYMETKICAL DISTRIBUTION. 



HISTORY. 



In regard to the bathymetrical distribution of Hexactinellida, Marshall^ gave in 

 1875 the following summary of the few results then available : — 



This list was extended by 0. Schmidt's ^ report upon the Hexactinellida collected by 

 A. Agassiz in the Gulf of Mexico, especially near the Lesser Antilles. This list, retaining 

 0. Schmidt's nomenclature, is given on the next page. 



From the above it wiU be seen that the depth varied from 100 to 2410 fathoms, with 

 the exception of the record of Cystispongia, said to have been found near Yukatan at a 

 depth of 20 fathoms. On this very divergent number of fathoms much weight must not be 

 laid, since there is a possibility of error or of misprint, all the more probable since at two 

 other localities the same species was found at depths of 136 and 292 fathoms. Leaving 

 this divergent instance out of account, we get from Alexander Agassiz's bathymetrical 

 statistics an average of about 500 fathoms, while 100 fathoms is the minimum depth at 

 which any form was found. Without attempting to gather up all the scattered reports 

 as to depths at which single Hexactinellid forms were found at various localities, I 

 shall content myself with noting that Dr. Doderlein^ found in the Sagami Bay, Japan, 

 various Hexactinellids (especially Aiohrocallistes, Fanned, and Hyalonema), at depths of 

 80 to 200 fathoms, It is also necessary to note some reports which have recently 

 appeared in the results of the French Expeditious of the " Talisman " and " Travailleur," 

 by M. Filhol* and M. Perrier.° According to these Pheronema were dredged from 



1 Marshall, Zdisckr. f. wiss. Zool., Bd. sxv. Supplement, p. 142. 



- Spong. Meerb. Mexico, 1880. ' Diiderlein Arcliiv f. Nahirgesch., Jahrg. xlix. BJ. i., p. 102, 1883. 



* La vie an fond des Mers. ^ Les explorations sous-marines. 



