all parts of their structure, external and internal, will show to be 

 distinct. But in some cases, as in the genus Delphinus, Dr. Gray s 

 distinctions, founded on size alone, have been allowed to stand pro- 

 visionallj at least, in the absence of more information as to the 

 extent of variation which may be attained in groups of individuals 

 to which the term " specific" may be legitimately applied. 



The List contains very nearly all the weD-established species of 

 the Order, the only notable deficiency being RhacManectes glaucus, a 

 whalebone whale of the North Pacific. Many species are, however, 

 very imperfectly represented in the Collection, either by a single 

 specimen or by a skull or other still smaller fragment of its organiza- 

 tion. The largest of all known mammals, Balcenojptera sibbaldii, is 

 represented only by the skeleton of a specimen scarcely more than half- 

 grown ; one of the most important forms, remarkable for the strange 

 modification of the mammalian type of structure which it exhibits, 

 and for the commercial interests involved in its capture, the Green- 

 land Eight Whale (Balcena mystieetus), by a skull in a very dilapi- 

 dated condition ; Berardius arnuxii, a large Ziphioid whale of the 

 South Seas, by a single tooth. Of nearly every species a larger 

 number of specimens is required to exhibit the, extent of individual 

 variation, and the modifications due to age, sex, or locality. 



It is hoped that the publication of this List, by showing the 

 deficiencies of the Collection, will aid in making it still more 

 complete. 



W. H. FLOWEE, 



British Museum Director. 



(Natural History), 

 May 1st, 1885. 



