STUDIES ON THE COMPARATIVE ANATOMY OF SPONGES. 33 



the pores. In the description of the type species (Teichonella 

 prolifera), however, we find the words "pores invisible to 

 the naked eye, scattered over the surface thickly, and generally 

 vents slightly marginated, . . . arranged more or less in a 

 single line along the margin only.^^ I have myself most care- 

 fully examined Teichonella prolifera by means of stained 

 sections cut by the paraffin method, and I find that it is 

 nothing but an ordinary Leucon, with pores on both surfaces 

 of the low, thick walls of which the sponge consists, and oscula 

 along the raised margin (fig. 6). The surface is certainly not 

 differentiated into anything like a pore-bearing and an osculum- 

 bearing plane. 



The fact appears to be that Polejaefi' wanted a place for his 

 new genus Eilhardia, and so he seized upon the Teichonel- 

 lidae and altered both the name and the characters of the 

 family to suit his own ideas, apparently without having so 

 much as ever seen a specimen of Teichonella. Of course, 

 both Teichonella and Eilhardia duly appear in an ela- 

 borate genealogical tree. 



Eilhardia, if Polejaeflf^s figures be correct, is a Leucon. 

 True, the pores appear to be on one surface and the oscula on 

 the other, but can anyone possessed of the slightest know- 

 ledge of the subject regard this as a family character ? I 

 think certainly not, and in support of my opinion venture to 

 call attention to the following extract from Ridley and Dendy^s 

 report on the " Challenger " Monaxonida (26) : — " Before 

 leaving the question of the pores we must consider briefly the 

 condition of flabellate sponges in this respect. It is an almost 

 invariable rule that in flabellate sponges the pores are to be 

 found on one surface and the oscula on the other. Thus in 

 Phakellia ventilabrum, var. connexiva (pi. xxxv, figs. 

 3, 3a; pi. xlix, fig. 3), and Phakellia flabellata, nobis 

 (pi. xxxiv, figs. 2, 3, 3 a), this arrangement is very well illus- 

 trated; and the same condition occurs in Myxilla frondosa, 

 nobis (pi. xxvi, figs. 1, la), and Gellius flabelliformis, 

 nobis (pi. xxvi, figs. 5, 5 a). Again, in that very remarkable 

 sponge, Esperiopsis Challengeri (pi. xviii), the pores 



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