356 Mr. H, J. Carter's Contributions to our 



I will now, however, go as fully into the subject as my means 

 will allow, summing up at the end the result of my investiga- 

 tions. 



These means consist of an examination of the type specimens 

 of Bowerbank's l J ethea muricata y Ecionemta compressa, Hyme- 

 niacidon placentula, and Normania crassa, an investigation of 

 many of the specimens of Tisip>lioniaagaric%fovmis ) together with 

 two of Normania crassa that were handed over to me by Sir 

 Wy ville Thomson and of one of the latter which I found on a 

 specimen of Azorica Pfeifferce in the British Museum ; and a 

 careful perusal of Prof. Sollas's paper on u Thenea Wallichii" 

 dredged by the Eev. A. M. Norman in the " Kors Fiord " of 

 Norway in 1878 (< Annals/ 1882, vol. ix. p. 427). 



Taking Tethea muricata first, of which a type specimen is 

 now before me labelled by Dr. Bowerbank himself, and almost 

 identical in general form with that described by him (Proc. 

 Zool. Soc. ; Feb. 1872, p. 115), and now in the British 

 Museum, its spiculation consists of the body-spicule, the zone- 

 spicule, and the three-armed, recurved, or anchoring-spicule 

 held together with sarcode which is charged with flesh- 

 spicules, all arranged as in Stelletta, that is : — that the body- 

 spicule is chiefly confined to the centre, but together with the 

 zone-spicule also forms bundles arranged more or less perpen- 

 dicularly to the centre in a zonular manner around the 

 circumference; the anchors or anchoring-spicules, together 

 with the free ends of some of the body-spicules, extend beyond 

 the circumference; and the flesh-spicules are chiefly con- 

 gregated in the dermal sarcode. When, however, this spicu- 

 lation is particularized, it is further found to possess features 

 so different from that of Btelletta and all other sponges that it is 

 typically distinct. Thus there are two forms of zone-spicules, 

 viz. a trifurcated and a simply trifid one ?, often only bifid 

 (" attenuate- expando-ternate bifurcating " and " simple- ex- 

 pan do- ternate " connecting-spicules of Bowerbank), of which 

 the arms of the former are so unusually extended that when 

 spread out in the dermal sarcode the latter look like the outer 

 or larger structure of a spider's web. The anchors, again, 

 whose heads or free ends are barbed (and when protruded, 1 

 may as well state once for all here, are very seldom preserved 

 in any of the sponges where they occur), appear to be confined 

 to the root-like appendages similar to the cord of Hyalonema 

 bieboldii ("radical processes " of Bowerbank, /. c), the proxi- 

 mal ends ot which are imbedded in the centre of the sponge 

 around the lower part of the cylindrical cloaca, which, after 

 having received all the branches of the excretory canal-system, 

 opens at the summit by a single wide osculum also like that of 



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