THE 



VOYAGE OF H.M.S. CHALLENOEE. 



ZOOLOGY. 



REPORT on the Siphonopiior^e collected by H.M.S. Challenger during 

 the Years 1873-76. By Ernst Haeckel, M.D., Ph.D., Hon. F.R.S.E., 

 Professor of Zoology in the University of Jena. 



PEEFACE. 



The Sipkonopkorse collected by tke Ckallenger during ker cruise round the world 

 were kanded to me for investigation in 1879. Tke examination of this material, 

 among which were to be found many new and remarkable types (especially abyssal 

 forms), led me to recommence my study of the organisation and development of 

 tke wkole class, wkick kad been interrupted for more tkan ten years. During a 

 residence of tkree months at Puerto del Arrecife, tke karbour of Lanzerote in tke 

 Canary Islands, December 18G6, January and February 1867, I kad tke opportunity 

 of becoming acquainted witk nearly all tke typical forms of tkis most attractive group 

 of animals. Tke facts wkick I tken discovered regarding tke curious, but till tben 

 little known, ontogenesis of tkese Acalepks, were embodied in a prize essay publisked 

 by tke Gesellsckaft fur Kunst und Wissensckaft in Utreckt. 1 I tken intended to 

 follow up tkis embryological memoir witk a more extensive comparative anatomical 

 one, or if possible a Monograpb, in wkick also tke systematic arrangement of tke 

 Sipkonopkorse skould be subjected to a tkorougk revision, and tke very intricate 

 literature of tkis class critically elucidated. Tke completion of tkis sckeme was, 

 kowever, deferred owing to various external kindrances, and tke rick material collected 

 at Lanzerote remained for tke most part unpublisbed. 



1 Ziir Entwickelungsgeschichte der Siphonophoren, Utrecht, 1869, 14 plates. 

 (ZOOL. CHALL, EXP. — FART LXXVII. — 1888.) Hhhh a 



