REPORT ON SPIRULA. 
29 
VIII. Ethology ok Bionomics. 
The conditions of existence of Spirula are almost entirely unknown. We 
know that the shells of this genus are thrown in very great numbers upon 
certain shores, and that, not being able to fall to the bottom on account of their 
lightness, they are often carried by currents to considerable distances. It is the same 
with the animal, when dead ; it is carried to the surface by its shell playing the role of 
float (for example: Peron’s specimen, those of the “Recherche” [Robert, 1856], and 
those of Professor Giard), or it may even be carried as far as some sea-shore (for 
example: Owen’s specimen [1879] and that in the Sydney Museum). But never has a 
Spirida been collected alive, at the surface nor even near the surface.^ 
Only two individuals have been dredged : one in 360 fathoms by the Challenger and 
one in 950 fathoms by the “ Blake,” and these individuals were dead. 
Spirula then is not a pelagic animal ; it must be an inhabitant of rather deep water. 
In fact if we examine the various known localities where Spirula has been met with, 
and those where its shell is thrown up in great quantities, we find that they belong only 
to a few principal centres : — 
1. Between Australia and New Zealand.^ 
2. Banda Sea.® 
3. West Indies.^ 
4. N. W. of Africa.^ 
However, in each of these centres, or very near them, is found, to use the usual term 
in physical geography, a “ deep ” or oceanic surface of relatively small extent, with 
a very rapidly increasing depth up to 2500, and even 4000, fathoms.® It may 
therefore be predicted with sufficient certainty that, to find perfect specimens of Spirula, 
it is necessary to search in deep water in one or other of the deeps here indicated. 
^ Gray (On the animal of Spirula, Ann. Mag. Nat. Hist., ser. 1, vol. xv. p. 259) says : — “ I am informed 
by M. Clausen that he had several specimens of this animal alive, and kept them some time in a vessel filled 
■with sea water, and that they had the power of ascending and descending at pleasure.” But from such an 
indefinite indication we cannot have any certainty that it was indeed Spirula, no other mention having been 
made by M. Clausen of such an important fact. 
2 Specimens of P4ron, of the Sydney Museum, and of Owen (1879). 
® Fragments of Rumphius (Amboina), of Owen (Timor), and Challenger specimen. 
4 “ Blake ” specimen. 
® Specimens of Cranch, of Robert, of Professor Giard, and another mutilated specimen which, 
Mr Craven, F.L.S., tells me, was taken between Madeira and the Canaries. 
® See especially the large chart (planisphere) accompanying the Narrative of the Cruise of H.M.S. 
Challenger. 
