REPORT ON THE HEXACTINELLIDA. 451 



The only representative of the genus Dactylocalyx procured by the Challenger 

 Expedition was found in the north temperate zone. On the other hand Myliusia 

 callocyathus and Aulocystis zittelii were found in several localities in the tropics. 



I have discussed in some detail the topographical distribution of the Challenger 

 Hexactinellida, because I believe that the uniformity of the exploring and collecting 

 methods, as well as the wide extent of the exploration, make the results of great value. 



In estimating the number of species obtained by the Challenger in different localities, 

 it is instructive to compare the statistics with those which are afforded us by the prolonged 

 and enthusiastic industry of Dr. Doderlein, who made during his lengthened residence 

 in Japan a collection of Hexactinellids, partly by purchase in Enoshima, and partly by 

 his own dredging in Misaki Bay near Tokio, which was also explored by the Challenger. 

 The results of his explorations have been described in detail in this Report along with the 

 Challenger material. His collection included in all 16 species : — 



1. Euplectella oweni, Marshall, dry. 



2. Acanthascus cactus, F. E. S., dry. 



3. Rhahdocalyptus mollior, F. E. S., dry. 



4. Crateromorpha meyeri, Gray, dry. 



5. Hyalonema sieboldii, Gray, dry. 



6. Farrea occa, Carter, well preserved in spirit. 



7. Farrea vosmaeri, F. E. S., dry. 



8. Farrea soUasii, F. E. S., dry. 



9. Periphragella elisse, Marshall, dry and well preserved in spirit. 



10. Aphrocallistes bocagei, Wright, in spirit. 



11. Aphrocallistes ramosus, F. E. S., well preserved in spirit. 



12. Apihrocallistes vastus, F. E. S., dry. 



13. Chonelasma da^derleinii, F. E. S., well preserved in spirit. 



14. Clionelasma calyx, F. E. S., dry. 



15. Hexactinella tubulosa, F. E. S., dry. 



16. Hexactinella cyathus, F. E. S., dry. 



On the Challenger Expedition three soundings were made in the Bay of Misaki, at 

 Stations 232, 236 and 236a, Station 232 yielded, from a depth of 345 fathoms, 

 several specimens of Hyalonema {Stylocalyx) afertum, and Station 236, from a 

 depth of 775 fathoms, a fragment of an undefined species of Dictyoniua. In the cursory 

 exploration of the Challenger only two Hexactinellida were thus obtained at the same 

 locality where the prolonged search of Dr. Doderlein was rewarded by finding 

 sixteen species. It is further of interest that among these sixteen species, the species 

 found by the Challenger — Hyalonema {Stylocalyx) apertum — is not included, though it 



