488 PROF. FLOWER ON THE DELPHINID^. [NoV. 20, 



that group), where the lateral margins are nearly parallel, and the 

 borders of the first three digits are in contact for nearly the whole 

 of their length . 



In the conclusion of tiie description of this skeleton I said : — " If 

 the osteological characters possessed by this specimen be found to 

 exist in other Dolphins with narrow compressed beaks and long 

 mandibular symphyses, Stem will be established as a natural group 

 of generic value." The result has been quite otherwise ; for the 

 skeleton described by Dr. Peters and that of the Chinese White 

 Dolphin clearly belong to two different types. For the first the 

 term Stem should be reserved. With what other known forms can 

 D. sinensis be associated? Since the pubhcation of the description 

 of its skeleton more information has been obtained regarding the 

 animals of the group, properly distinguished by Gray as a special 

 form, to which he gave the name of Sotalia, and the indications of 

 the similarity of D. sinensis to D. guianensis, the type of the group, 

 already pointed out, can be more comj)letely developed \ Edward 

 Van Beneden has given a very full description of the external and 

 osteological characters of a specimen taken in the Bay of Rio, where 

 it appears to be of very common occurrence. Unfortunately the 

 individual upon which his description is based was an exceedingly 

 young one ; and the imperfect development of the bones not only 

 accounts for some of the pecuharities he noticed, but also renders a 

 comparison with other specimens less satisfactory than it otherwise 

 would be. G-ervais has given figures and some details of the osteo- 

 logical characters of another species from the Amazon, B. pallidus ; 

 and the British Museum possesses two skulls, also of very young indivi- 

 duals, obtained by Mr. Bates near Santarem, on the Upper Amazon, 

 described by Dr. Gray under the name of Steno tucuxi. That these 

 are all very closely allied forms there can be no question ; but the 

 materials are not yet sufficient to work out their specific characters 

 or geographical distribution. At present they have been found on the 

 coast of Guiana, in the Bay of Bio, and in the upper waters of the 

 Amazon. From the published descriptions it is very difficult to 

 find any characters by which the Delphinus paUidus of Gervais, Steno 

 tucuxi of Gray, and Sotalia brasiliensis of £. Vau Beneden can be 

 distinguished specifically. 



To this group I have now no hesitation in adding Delphinus sinensis. 

 It is curious that it agrees with the American form of which we 

 have the fullest description (*S^. brasiliensis) in its pale coloration, 

 and in its habit of frequenting estuaries and Ijays, and not the open 

 sea. 



A cranium in the Museum of the College of Surgeons, found upon 

 the sea-beach at Aripo, in the north of Ceylon, by Mr. E. W. H. 

 Holdsworth, closely resembles that of D. sinensis, but is of smaller 

 size. 



Another anim.al apparently of the same group is Delphinus 



' Sec"Memoire sur un Dauphin nouveau de la Bale cle Eio de Janeiro, 

 Sotalia hrasiliensis," by Ed. Van Beneden: Mem. de I'Acad. Roy. de Belgique, 

 t. xli. 1874 ; and Grervais, in ' Osteographie des Cetaces,' p. .594. 



