132 Dr. R. von Willemoes-Suhm on the [Dec. 9, 



IV. The metamorphosis of the Cypris into the young Lepas. 



1. The pupae are chiefly caught at the very surface of the sea, where 

 they swarm round the dead Veldlce, on which they settle. They rarely 

 take to a colony of old barnacles. 



2. Soon after settling the new cirri are formed underneath the nata- 

 tory feet, the head grows out, the eyes are absorbed, and under the 

 Cypris-shell the primordial valves of the young Lepas appear, which 

 persist during its whole life. The Cypris-shel], with the old natatory 

 feet, is then thrown off. 



3. The young Lepas begins to form the complete shell, and fastens 

 itself more and more by the copious secretions of its glands, which run 

 through the outdrawn and enlarged head into the fixing-antennae. 



4. The cirri of the young Lepas develop a larger number of joints, the 

 shell begins to lose its transparency, the body inside turns over a little, 

 as has been described by Darwin, and the young Lepas is complete. 



Conclusion. 



1. As the young stages of the Lepadidae are pelagic, it is only 

 possible to work out their development at sea, and there at certain 

 seasons. We found ouly once before the large Nauplii of Lepas australis. 

 The development of no one of the Lepadidae has hitherto been known in 

 full ; and it seems that even the adult larvae of our commonest barnacles, 

 such as L. anatifera and L. aserifera, are as yet unknown. 



2. The Nauplius stages of Lepas fascicularis have not a different 

 morphological value from those of Balanus and other genera ; therefore 

 there is no reason for giving to this stage a particular name. The term 

 " Archizoea " may remain as a remembrance of Dohrn's interesting 

 discovery, but cannot be applied to the larvae of other Lepadidae. 



H.M.S. ' Challenger,' Honolulu, 

 July 28, 1875. 



III. " Preliminary Remarks on the Development of some Pelagic 

 Decapods/'' By R. von Willemoes-Suhm, Ph. D., Naturalist 

 to the ' Challenger 3 Expedition. Communicated by Prof. C. 

 Wyville Thomson, F.R.S. Received September 28, 1875. 



Since we left Australia I have investigated the metamorphoses of some 

 Crustacea which have been constantly caught by us on the surface of 

 the tropical and subtropical parts of the Pacific. Though these investi- 

 gations will be continued, I have now arrived at certain results which I 

 think will not be uninteresting to zoologists. The genera to which 

 these remarks refer are Amphion, Sergestes, and Leucifer. 



Amphion Beynaudi has been on our lists as an animal " incertm seclis 

 (Milne-Edwards) for nearly forty years, until Dohrn proved that a full- 



