Knowledge of the Spongida. 359 



Of Tisiphonia fenestrate*, Sdt., from Bequia, near St. Vin- 

 cent in the West Indies (Spong. des Heerbusen v. Mexico, 

 1880, 2. Heft, S. 71, Tat 1 , x. fig. 2), I can state nothing, further 

 than what may be learnt from the description and illustrations, 

 viz. that in form it is nearly allied to Wyvillethomsonia 

 Wallichii, and that its spiculation presents no essential dif- 

 ference. 



We come now, however, to a very different form in this 

 group, viz. one that is sessile, and not pedunculate like the 

 foregoing; I allude to u Normania crassa" of which I now 

 only possess the slides of those dredged on board H.M.S. 

 ( Porcupine,' a specimen of that on Azorica Pfeifferce, and my 

 " Notes " of these and the other two so-called species, viz. 

 Ecionemia compressa and Hymeniacidon placentula, Bk., to 

 which I have above alluded. 



In all these the spiculation is so much alike when the type 

 specimens themselves are examined (but not Dr. Bowerbank's 

 illustrations, Mon. B. S. vol. iii., in two of which, viz. Nor- 

 mania crassa and Hymeniacidon placentula, the spined and 

 centrally inflated spicules, and in the latter the smaller size of 

 the flesh-spicule also, are omitted, although alluded to in the 

 descriptions respectively) that they appear to me to be one and 

 the same species. The body-spicule is, of course, present 

 as a large long acerate ; but the zone-spicule is hardly more 

 than rudimentary — that is, reduced to a simple trifid (" attenu- 

 ato-patento-ternate connecting spiculum," Bk.), in which, as 

 in Tethya merguiensis (a new species of Tethyina to be de- 

 scribed hereafter), the shaft is hardly to be distinguished in 

 point of form and length from the arms, while the " unusually 

 long bifurcated trifid " is altogether absent. There are of 

 course no anchor ing-spicules ; but the flesh-spicules, both large 

 and small, are the same ; added to which there is a more or less 

 centrally inflated spined acerate, which, in conjunction with 

 the rest of their differences, distinctly distinguishes this species 

 from the type of Tethea muricata and from Wyvillethomsonia 

 Wallichii. Prof. Sollas therefore is quite right when he 

 states that they are "generically different, although nearly 

 allied " to Normania crassa (p. 433, /. c). 



1 certainly did use the expression " similar variety of Te- 

 thea muricata" with reference to Hymeniacidon placentula 

 and Normania rrassa, in my attempt to show that Bowerbank's 

 work could claim the earliest mention of these sponges ( c An- 

 nals,' 1878, vol. ii. p. 176), of which Schmidt says, " Ich 

 schliesse miek dieser Ansicht durchaus an." But it wasonlj 

 done cursorily j for at that time I was engaged in going through 

 the whole of Dr. Bowerbank's type specimens of his British 



