EDITOKIAL NOTES. 



This volume contains Parts XVIII., XIX., XX., and XXI. of the Zoological 

 Series of Reports on the Scientific Results of the Expedition. 



Part XVIII. — During the cruise in the Southern Hemisphere, the 

 Naturalists of the Expedition preserved, in addition to the collection of skins, 

 a large number of young and adult Penguins in salt and spirit. This 

 collection was, on the return of the Expedition, placed in the hands of Dr. 

 Morrison Watson, Professor of Anatomy in the Owens College, Manchester, 

 for examination, and this elaborate Memoir gives the result of a painstaking 

 examination into the anatomy of all the species obtained. 



Part XIX. — The special work of the Challenger Expedition was the 

 examination of the Physical and Biological conditions of the great Ocean 

 Basins, and the detailed Official Reports on the Scientific Results of the 

 Expedition will — with few exceptions — be limited to those departments of 

 research referring more or less directly to the Ocean. The large collections 

 of Insects, Land Shells, Spiders, Amphibians, Reptiles, and Mammals, made 

 by the Naturalists on land at the various ports and islands touched at 

 throughout the cruise, being regarded as " Incidental Collections," have been 

 deposited in the British Museum, to be examined by the officers in charge of 

 the national collections. These " Incidental Collections " will be referred to 

 in the volumes containing the Narrative of the cruise, but it is not proposed 

 to publish any detailed Reports concerning them. 



The only Insects having a truly oceanic habitat belong to Halohates and 

 one or two allied genera, and consequently this Memoir, by Dr. F. Buchanan 

 White, on those Pelagic Hemiptera, is the only one relating to the class 

 Insecta which will appear in the series of Challenger Reports. 



