REPORT ON THE MONAXONIDA. 



XI 



is enlarged to include the Keratosa, while the name Monaxona is made more or less 

 exactly synonymous with the older Monaxonida ; thus : — 



Subclass 1. Hexactinellida, 



Subclass 2. Demospongiae, , 



Subclass 3. Myxospongiee, 



PORIFEEA (Phylum). 

 Class I. Plbthospongi*. 



{ Tribe a. Monaxonida, 

 I Tribe h. Totractinellida, 



Class II. Calcispongia. 



Order 1. Lyssakina (Zittel). 



„ 2. Dictyonina (Zittel). 

 Order 1. Monaxona. 



„ 2. Ceratosa (Grant). 

 Order 1. Choristida (Sollas). 



„ 2. Lithistida (O. Scdt.). 

 Order 1. Halisarcosa(O.Scdt.). 



„ 2. Chondrosiosa. 



Finally, Dr. E. von Lendenfeld has, in a paper recently read before the Zoological 

 Society of London,-^ given an elaborate scheme of classification of Sponges agreeing 

 more or less closely in its main features with that of Dr. Vosmaer, and adapted, as 

 regards the smaller subdivisions, from the most recently published works on the 

 subject. To this paper we would refer the reader who seeks for further information on 

 this much-vexed question. As the portion of the scheme bearing upon the Monaxonida 

 is derived chiefly from our own Preliminary Report we need not here discuss it in 

 detail. 



We must, however, point out one very serious error in Dr. von Lendeufeld's j^aper, 

 which appears to be a misjjrint. We refer to the use of the name " Monaxonida " 

 on p. 583, instead of " Monaxonia," as opposed to the "Tetraxonia" on p. 580. 

 We point this out as such a mistake is likely to lead to great confusion, for the 

 term Monaxonida as used by Dr. von Lendenfeld in this place has a significance very 

 diff"erent from that of the same term as used by ourselves. 



' Proc. Zool. Soc. Land., December 21, 1886. 



