1883. } Zoology. 1183 
seat of the amceboid movements, which take place chiefly at the 
superior extremity, where the endodermic axis is wanting, 
cause of the movements is explained by the structure of the ecto- 
derm. Its cells are immersed in a contractile protoplasmic mass, 
to whose contractility the movements are due. 
Though these organs have no cavity they may be considered 
as degenerated polyps : (1) Because their tissues are the same ; (2) 
because each has a calyx, and (3) because the polyps can, in cer- 
tain circumstances, transform themselves into a nematophore. 
The author’s observations were made on one species of Plumu- 
laria, two of Antennularia and two of Aglaophenia. In the case 
of one of the latter he found that the tissues constantly contained 
parasitic alga; the endoderm “ yellow cells,” and the ectoderm a 
green alga belonging to the Phycochromacee.— Journal of the 
oyal Microscopical Society. 
deep-water forms, and they may, with all the more reason, 
Said to characterize the abyssal fauna, as no single representative, 
r as is at present known, has been found to exist at a depth 
less than fifty-eight fathoms. Only one form, E/pidia glacialis, has 
here been dredged at such an inconsiderable depth, and even this 
was dredged in the Arctic ocean, where true abyssal forms are to 
be met with at comparatively shallow depths, This species, too, 
can exist at immense depths, one form, Station 160, having been 
dredged at a depth of 2600 fathoms; the greatest depth at which 
any Holothuroid has hitherto been dredged being 2900 fathoms. 
ong the more remarkable and distinguishing characteristics 
of this order, Herr Théel mentions the agreement in several im- 
Portant details, both in their internal anatomy and outer form, of 
the adult and larval states; an agreement more close than occurs 
’ 
1 * 
the Reports on the Scientific Results of the voyage of H. M. S. Chale during 
"ts 1873-6, Vol. tv (1882), pp. 176, and 46 pls. Cf. Mature, XXVII. 
