Prof, E. Eay Lankester on Hamingia arctica. 37 



Fig. 5. The same. Fragment of fibre in a thin slice, mounted in Canada 



balsam, as seen by transmitted light under a microscopic power 

 of about 125 diameters, a, shaft of axial spicule (? of a colossal 

 radiate) ; b, short conical arm, or spur, projecting from it, show- 

 ing in this instance that it is spinif 'era us ; c, edges of the laminae, 

 forming the fibre outside the axial spicule, crenulated. 



Fig. 6. The same. Showing that the outer layer of the fibre may be 



tubercled. a, axial spicule ; b, edges of fibre-laminae. 



Fig, 7. The same. Showing two rays or spurs near each other on the 



same axial spicule, a, axial spicule and spurs ; b, edge of fibre- 

 lamina. 



Fig. 8. The same. Showing that the fibre-laminse may also project 



spurs. a } axial spicule, bearing one spur ; b, fibre-laininte, bear- 

 ing two spurs near each other. 



Fig. 9. The same. Showing that the fibre-lamina follows the form of 



the spur on the axial spicule, a, axial spicule and spur ; b, fibre- 

 lamina. 



Fig. 10. The same. Showing that the axial spicule is composed of con- 

 centric laminae. «, axial spicule ; b y fibre-laminae. 



Fig. 11. The same. Showing the arms of a tri- or quadriradiate spicule 



in the axis of the fibre, a, radiate spicule; b, fibre-lamina. 



Fig. 12. The same. Showing spurs and crenulated laminre close to the 



axial spicule, a, axial spicule ; 6, fibre-lamina. 



Fig. 13. Leiicetta clathrata, n. sp., on a foliaceous coralline, a, Calci- 



sponges. Nat. size. 



Fig. 14. The same. Magnified eight diameters, to show the vermiculo- 



reticulation of the clathrous structure on the surface. a y os- 

 c ulum. 



Fig. 15. The same. Surface of vermiculo-reticulation, to show that it 



is composed of spicule No. 16, covered in by No. 17. a a, sum- 

 mits of No. 16 ; b b, lateral view of the same ; cc, No. 17. 



Fig. 16. The same. Colossal triradiate or tripod spicule. Lateral view. 



Fig. 17. The same. Smaller triradiate of the staple kind. Horizontal 



view. (Both of the average largest size, magnified equally, to 

 show their relative dimensions.) 



IV. — On Specimens of the Gephyrean Hamingia arctica, 

 Kor. and Dan., from the liar danger Fjord. By E. Ray 



Lankester, M.A., F.R.S., Professor in University College, 

 London. 



In the ' Zoology (Gephyrea) of the Norwegian North-Atlantic 

 Expedition,' published at Christiania in 1881 ^ the distin- 

 guished Norwegian naturalists Koren and Danielssen, who 

 have so long and so well worked together, describe, amongst 

 other interesting novelties, a very remarkable Gephyrean 

 allied to Bonellia, of which a single specimen came into their 

 hands, having been dredged two hundred miles north of the 

 North Cape. They gave to this the name Hamingia arctica. 

 Later in the same year (1881) Dr. Horst, of Leyden, de- 

 scribed (NiederL Archiv fur Zoologie, Supplementband L) 



