SILICIOUS AND HOjRNY SPONGES WILSON. 275 



oxea. But oxea in the singular is now a well-recognized word, classi- 

 fied as modern Latin by the dictionaries, having arisen as a viable 

 form through Professor Sollas' operation on the Greek adjective. 

 Oxeon would seem to be a word of contemporary coinage and un- 

 necessary. The adjective should then be oxeate and not oxeote. 



For the precise location and characteristics of the stations at which 

 sponges were taken I refer to United States Bureau of Fisheries 

 Document No. 741 (Dredging and Hydrographic Records of the 

 U. S. Fisheries Steamer Albatross during the Philippine Expedi- 

 tion, 1907-1910. Washington, 1910). 



An outline of the classification followed in this report is here 

 given : 



Class Noncalcarea Vosmaer, 1887. 



Order 1. Myxospongida Dendy, 1905 (Myxospongiae part Len- 

 denfeld, 1885, history of term here reviewed; Myxospongiae Sollas, 



1888, p. xcvin). — Simple forms without a skeleton. Absence of 

 skeleton primitive. The genera are Halisarca Dujardin, 1838, Osca- 

 reUd Vosmaer, 1887, Bajulus Lendenfeld, 1886, Hexadella Topsent, 

 1896. With regard to the position of these sponges there is marked 

 disagreement. Lendenfeld, 1889, 1894c, looks on Halisarca and 

 Bajulus as degenerate derivatives of Darwinella and assigns them 

 to his Hexaceratina (in the Triaxonia), to which group Topsent, 

 18966, also assigns Hexadella. Oscarella is separated by Lendenfeld, 



1889, 1903, 1906, from the other genera of the group, as here under- 

 stood, and transferred as a family (Oscarellidae) to the Homo- 

 sclerophora (Microsclerophora). Hentschel, 1909, 1912, follows the 

 same practice and further combines Hexadella with Oscarella. 



Order 2. Hexaotinellida O. Schmidt, 1870 (Triaxonia, IF. E. 

 Schulze, 1887). — With triaxonid (characteristically hexactinellid) 

 siliceous spicules. 



Order 3. Tetraxonida Dendy, 1905 (Demospongiae Sollas, 1888, 

 minus Ceratosa). — The characteristic form of spicule is a siliceous 

 four-rayed sclerite, each ray rep resenting a particular axis (tet- 

 raxonid or tetractinellid spicule). But in some groups these spicules 

 have been lost. 



Suborder 1. Homosclerophora Dendy, 1905. (Microsclerophora 

 Sollas. 1888; Microsclerophora part Lendenfeld 1889). 



Family 1. Plakinidae F. E. Schulze, 1880.— The genera are Pla- 

 kina F. E. Schulze, 1880; Plakortis F. E. Schulze, 1880; Plakinas- 

 trella F. E. Schulze, 1880 (assigned by Sollas, 1888, to Theneidae, 

 by Dendy, 1905, to Pachastrellidae) ; Dercitppis Dendy, 1905. 



Family 2. Corticidae Vosmaer, 1887, Sollas, 1888.— Lendenfeld, 

 1903. deletes the family. The genera arc Corticiurn (). Schmidt. 

 1862 (assigned by Lendenfeld, 1903, to the Plakinidae) ; Calcabrina, 

 Sollas, 1888 (synonymous with Stoeba Sollas, 1888, according to 



