THE 
VOYAGE OF H.M.S. CHALLENGER. 
ZOOLOGY. 
REPORT on the Pteropoda collected by H.M.S. Challenger during the 
Years 1873-76. By Paul Pelseneer, D.Sc. (Brussels). 
PART III.— ANATOMY. 
INTRODUCTION. 
The collection of Pteropoda, preserved in alcohol, brought home by the Challenger, 
includes specimens of all the known genera except Cymbuliopsis and Clione. 
This collection having been placed in my hands for purposes of systematic study, I 
was, when this part of the work was concluded, in an exceptionally favourable position 
for undertaking a monographic examination of the organisation of this group of animals. 
Since the publication of Souleyet’s memorable work, the anatomy of the Pteropoda has 
been studied almost exclusively by means of European species, and this is the first time 
since that epoch that such an important collection as the present one has been made, 
including, as it does, forty-four species out of the sixty-three actually known, and 
specimens of nearly all the genera. 
Hence although the time at my disposal was very limited, I could not allow an oppor- 
tunity to escape which would probably not soon occur again. 
By adding to the Challenger collection some specimens of Clione limacina which 
Mr. John Murray placed at my disposal, and a specimen of Cymbuliopsis of my own, I 
was able to investigate all the known genera of Pteropods, so that the conclusions at 
which I have arrived have not been drawn from the organisation of a few species only, 
(ZOOL, CHALL. EXP. PART LXVI. — 1888.) Uuu 1 
