42 On Arctic and Antarctic Sponges. 



Jar No. 2. 



Contains specimens of Halicliondria panicea, Johnston (Sjyoyi- 

 gia2yapiUw-is, Grant), of the coast, but with larger spicules and 

 the histodermal coat peculiar to the deep-sea form ; a small 

 Actinia ; and a sprig of a branched, colourless, horny Poly- 

 zoon. 



s 



Jar No. 3. 



Contains a single specimen only, viz. a calcareous sponge 

 [Sycon raphanuSj Sdt.). 



Jar No. 4. 



Contains one specimen each of the calcareous sponges Ute 

 glabra, Sdt., and Leiicosolenia coriacea, Bk. [Ascetta coriacea^ 

 Hackel) ; also sprigs of three kinds of branched Polyzoa, 

 one calcareous. 



» Jar No. 5. 



Contains three fragments of Melohesia polymorpha only, 

 which was sessile. 



I have mentioned all the other organisms which these jars 

 contain besides the sponges to show that the sea-bottom, both 

 in the arctic and antarctic regions, at least so far as regards the 

 latitudes mentioned, is as pregnant with life as that of any 

 other part of the globe, at the same time that it has its pecu- 

 liarities. 



The specimens have been examined and returned to the 

 British Museum without delay. 



EXPLANATION OF PLATE I. 



Fig. 1. Semisuberitea arctica, n. sp., growing on the outer shell of a Bala- 

 nus. Natural size. Smith Sound. Lateral view, a, stem ; b, 

 funnel-shaped head ; c, margin; d, Balaims-shQW] e, Pedicellina 

 gracilis ; f, Alcyoniiim ; g g, stems of 8. arctica broken otf ; h, 

 dotted line indicating opposite border of mouth. 



Fig. 2. The same, from Spitzbergen. Natural size. Lateral view, o, stem ; 

 b, funnel-shaped head ; c, pore- or external surface ; d, vents on 

 internal surface ; e, rounded margin. 



Fig. 3. The same, spicules magnified on the scale of l-12th to l-1800th 

 inch, a, acuate form ; b, subpinlike form. 



Fig. 4. Single cell oi Alcyoniuin, 11^. l,f, magnified. 



Fig. 5. Head of Pedicellina grac '-i, magnified, to show the organs of the 

 interior, a, stem ; b, calycle ; c, oral orifice surrounded by ten- 

 tacles ; d, anal orifice ; e, stomach ; /, tentacles. 



