THE 
VOYAGE OF H.M.S. CHALLENGEK. 
ZOOLOGY. 
REPORT on the Specimen of the Genus Spirula collected by H.M.S. 
Challenger. By the Rt. Hon. Tnos. H. Huxley, F.R.S., and Paul 
Pelseneer, D.Sc. (Brussels).^ 
INTRODUCTION. 
In the animal kingdom there are some exceedingly rare forms, — the number of 
observed individuals may be counted, — to which zoologists attach very great interest 
because of their phylogenetic importance ; this arises either from their being the 
sole representatives of groups on the way to extinction, or because they permit us 
to form a better conception of the relations existing between groups which appear 
sharply separated from each other. 
Spirula is one of these forms, and it is certainly of all Molluscs that which the best unites 
to the interest of rarity an aberrant conformation among the existing animals of its class : 
it is the only Dibranchiate with a multicellular, siphonated, and partially- external shell. 
Rumphius is generally credited with being the first to observe a Spirula, and with 
having even given us some details as to its manner of life. From a consideration of 
the passage which he devotes to this genus ^ I am convinced that he saw only some very 
unimportant fragments (the adherent part of the last septum and the siphuncle) ; he 
believed the last chamber to be much larger, as in Nautilus, and he imagined that the 
nephalic part of Spirula remained fixed [see further on] to the rocks, the edges of the 
last chamber of the shell being supposed by him to be broken. 
The first almost complete, though mutilated, specimen was collected by Peron and 
Lesueur, and from it Lamarck, who had created the genus for the shell (1799), first 
made known the existence of suckers.® Peron gave a rather unsatisfactory figure of 
1 See Editorial Note for statement as to the collaboration between the authors in the preparation of this 
Report. The Report was translated from the French by Miss Annie Sclater. 
2 Rumphius, D’amboinsche Rariteitkamer, 1705, pp. 67, 68. 
^ Lamarck, Encyclopedic methodique. Atlas des Vers, Mollusques, Zoophytes, pi. 465, fig. 5, a, 1827. 
(ZOOL. CHALL. EXP. — PART LXXXIII. — 1894.) 1 
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