THE 



VOYAGE OF H.M.S. CHALLENGER. 



ZOOLOGY. 



REPORT on the Cirripedia collected by H.M.S. Challenger during the 

 years 1873-76. By Dr. P. P. C. Hoek, Membei of the Royal 

 Academy of Science of the Netherlands. 



ANATOMICAL PAET. 



INTRODUCTION. 



One of my principal reasons for wishing to investigate the Cirripedia dredged during 

 the cruise of H.M.S. Challenger was the hope that I should be able by the aid of the 

 deep-sea material to enlarge our knowledge of the morphology of the order. It was 

 possible that among the forms from considerable depths there might be some which on 

 account of their great size, or for other reasons, would be especially favourable for 

 anatomical research, as was the case with some of the Pycnogonids from the abysses. 

 It was possible also that among them a new form might occm-, the investigation of 

 which would cast light on details in the organisation which had not hitherto been suffi- 

 ciently understood. In this respect, however, the study of the deep-sea material has 

 somewhat 'disappointed my expectations ; the new forms for the most part arc represented 

 by single specimens only, or are too small to be dissected advantageously. I have 

 therefore been obliged to limit my researches entirely -to such forms as were previously 

 known and had served for the researches of former investigators. They belong to the 

 genera Lepas, Conchoderma, and Scalpdlum of the pedunculated Cirripedia, and to the 

 genus Balanus of the sessile Cirripedia. What I have been able to work out docs not 

 form a connected whole, but may conveniently take the form of separate chapters in the 

 morphology of the group. 



(ZOOL. CHALL. EXP. — PABT xxviu. — 1884.) te 1 



