OBSERVATIONS OX THE EUPLECTELLID-E GENERALLY. 25 



Whether or not tlie Holascinse, made up of the two genera 

 Holascus and 3Ialacosaccus, and the Euplectellin», consisting of 

 the single genus Eujjlectella, are to be kept separate, is, I should 

 think, largely a matter of opinion. To me it appears that the 

 two subfamilies had better be united into one, chiefly because 

 the main distinctive character that has l)een assumed as existing 

 between them, — viz., the absence or presence of orifices on the 

 lateral wall, — has been discredited by the recent discovery of 

 3Ialacosaccus floricomatus Tops., in which a number of orifices, 



Whether or not the palîwzoic lyssaciue forms, put together by ScnBAMMEN ('02) under 

 a distinct suborder, the Stauractinophora, are to be looked upon as really representing a 

 phylum systematically nearly equivalent to the Amphidiscophora or the Hexasterophora, I 

 prefer to leave undecided, owing to uncertainties that always attach to the fossil Hexactinellids 

 in respect of the finer spiculation. 



The Hexasterophora I assume to have early split into at least three branches or tribes, 

 to be here provisionally called A, B and C. 



Tribe A, which may be allowed to retain Zittel's name Lyssacina but in an altered 

 sense, comprises ail the hexasteropliorous lyssacine families, of which I distinguish four, viz., 

 Euplectellidse, Leucopsacidse, Caulophacidse and Rossellidœ. 



Tiie other two tribes are both dictyonine and together correspond to Zittel's Dictyonina, 

 but are probably not to be put together under one such systematic group. 



Under Tribe B, which in scope nearly agrees with F. E. Schulze's Inermia, I place 

 the family Dactylocalycidre (made up of the genera Daclylocalyx, Mai'fjariteUa, Ifyliusia, 

 Aulocalyx and Euryplegma) as well as all the lychniscophorous forms, both recent and fo.ssil. 

 Schrammen (1. c.) though essentially in agreement with F. E. Schulze and with me as 

 regards the principles of classification, stands in practice at variance with the view here 

 advanced in that tiie Lychniscophora SciiR. is made by him into a suborder distinct from 

 another, the Hexactinophora Schr., wdiicli latter is made up of the Tribes Aniphidiscophora, 

 Hexasterophora and Uncinataria. That writer evidently lays undue weight on the lychnisc. 

 This in my opinion is formed simply by the addition of peculiaidy arranged synapticuloe 

 around the central node of hexactins composing an ordinary dictyonal skeleton. The 

 Lychniscophora then seems to me to be just as much a Hexactinophora as any form referred 

 by Schrammen to this group. And furthermore, it is certainly a Hexasterophora, as is 

 proved by what we know of the living lychniscophorous genus Aitlocystis. 



Tribe C is exactly identical with F. E. Schulze's Uncinataria. The spicules called 

 uncinates, from which the tr'.be received tlie name just mentioned, are peculiar in that 

 they can not be proved to be secondarily derived from a triaxon owing to the absence of 

 the axial cross, though the axial canal is present. A noteworthy fact it is that the same 

 spicules occur also in certain Amphidiscopliora, though not in all. Tliis seems indicative 

 of a near phylogenetic relation between the Lncinataria and the Aniphidiscophora, but just 

 how it is sea: cely possible to determine, 



