Catalogue of Non-Calcareous Sponges. 235 



As regards the notes on the colours of the living sponges 

 supplied by Mr. Wilson, and forming a most valuable contribution 

 to our knowledge of the group, I may remark that a large 

 number of them are based upon a comparison of the specimens 

 with the plates in Ridgway's " Nouaenclature of Colors for 

 Naturalists" (Boston, 1886), and that in these cases I have made 

 use of the nomenclature of that author. 



The present instalment, forming Part I. of the catalogue, 

 includes only the Families Homorrhaphida^ and Heterorrhaphidje 

 of the Order Monaxonida. Although I am aware that consider- 

 able modification will doubtless have to be made in the classifi- 

 cation of the Monaxonida as proposed by Mr. Ridley and myself 

 in our " Challenger " Report, and that much valuable work in this 

 direction has of late years been accomplished, especially by iNIr. 

 Topsent, yet I have decided to adhere for the present to our origi- 

 nal scheme. I have done so because the "Challenger" Reports form 

 an accessible and recognised standard of reference, and because 

 the proposed modifications can hardly, in the present state of our 

 knowledge, be considered as final. It may, however, be desirable 

 to incorporate souie minor and undoubted improvements at once, 

 and in order to facilitate the work of the student I give diagnoses 

 of the families, sub-families and genera as here employed. The 

 spicular terminology is tliat of the "Challenger" Report on the 

 Monaxonida. 



The proportion of new species is, as might be expected from 

 the extent of the collection, large. Thus, in the present 

 contribution, out of a total of thu'ty- seven species seventeen are 

 described as new. 



The abbreviations made use of in the literature references will, 

 I hope, explain themselves. The most frequent is "A.M.N.H.," 

 which of course stands for "Annals and Magazine of Natural 

 History." 



Order MONAXONIDA. 



Siliceous sponges with uniaxial megascleres. 



Family HOMORRHAPHID^. 



Megascleres all diactinal, either oxea or strongyla ; no micro- 

 scleres. 



q2 



