PORIFERA. I. 



chaliiia oliin) I have thoTight it correct to break up tlie group Phlceodictyincs^ and classed its two 

 genera, one with Homorrkapkidce, the other witli Heterovrliaphidce. 



It would seem as if the larvae in the Motiaxonida show group characters (Maas, Top sent), 

 and it is not improbable that the systematism will be highly altered, as for inst. Bidder has altered 

 the systematism of the calcareous sponges according to quite new and at all events verv interesting 

 views. At present, however, I think the division of the sub-order Halichoiidriiia into the families 

 Homorrhaphidce ^ Heteyorrhaphidcv , Desinacidoiii'dcr and Axinellidce to be the most natural — as also 

 the most practical one. 



Order Monaxonida. 



Suborder I. Hdlichondrina. 

 Fam. I. Homorrhaphidae. 



Subfam. I. Chalininae, 



The subfamily Chalinina; the onh- distinghuishing character of which is the amount of spongin 

 uniting the spicules into fibres, cannot, as has also been generally recognized, be kept sharply distinct 

 from the Renierince^ as the least sponginous forms form a transition to these latter, while on the other 

 hand forms with much spongin and reduced spiculation form a transition to the horn\- sponges. In 

 the present work I have tried to make the distinction in the following way: to be referred to the 

 Chalinince a species must have at any rate the primary fibres quite sponginous, even if the mass of 

 spongin is small. If this is not the case, I refer the species to the Rcniera, even if, as is the case in 

 several species of Reniera^ separate longitudinal fibres with a rather large amount of spongin are to 

 be found; neither do I take into consideration a higher development of spongin in the basal part or 

 stalk of the sponge. When the distinction is established in this wa>-, we shall, in by far the most 

 cases, get an outer characteristic, viz. the consistency; even Chalinina' with very little spongin will 

 show an elasticity that is not found in the Reniera-'i^tci&s. Thus the distinction seems to me to be 

 in most cases quite natural, although it cannot be said to have solved the question. 



While it is thus very difficult to mark off the whole group, it is not much better with regard 

 to the genera. Many of these are based on characters running gradually into each other, as for inst. 

 on the number of spicules in the fibres, by which character it has been tried to distinguish between 

 Pachychaliiia and Chaliiia, although there is no distinct difference; also the outer form has been 

 used as a distinguishing character, by Lendenfeld even to an extreme degree. It is to be supposed 

 that the great number and richness in forms of the Chalinince have led to this condition of things, 

 for it may be said, I think, that this subfamily, a few particular forms excepted, has no more value 

 as a systematic group than the genus Reniera\ this genus might be divided into genera after the 

 same characters, but the limits between these genera would be doubtful; several of the characters, 

 taken for inst. from the skeleton and the surface, by which genera of the Chalinince are characterized, 

 are in the Reniera iised as specific characters. There has, however, been no opportunity for a more 



