AND OTHER SPECIES OF CEPHALORHYNCHUS. 631 



External measurements of Mr. Hamilton's specimen (A) : — 



Cm. 



Total length 137* 



Dorsal fin (middle) to tip of snout 81 



,, ,, ( J, ) to emargination of tail 63"5 



,, ,, length of base 22*8 



Flipper, length, from axilla 16'5 



,, ,, inferior border 23"5 



Gape, length of, from tip of upper jaw ... 16*5 



Snout to blow-hole 20*3 



Tip of lower jaw to (middle of) umbilicus.. 64 



Umbilicus to reproductive aperture f 14 



Reproductive aperture tc anus 1 8'5 



Anus to emargination of tail 40"5 



The characters of Cephalorliynchus Gray Avere re-defined by 

 Flower, in his well-known paper on the Delphinidfe (1883, p. 473), 

 the type-species being Delphimts heavisiclii Gray, 1828. In his 

 Review of the Delphinidse, True (1889, pp. 108, 176) recognises 

 four species of the genus — the type-species from the Cape of Good 

 Hope, C. albifrons Triie and G. hectori Yan Beneden from 

 New Zealand, and C. eutropia Gray from Chili. In 1893 and 

 ] 896 several new Dolphins from Chili were described by R. A. 

 Philippi. His two papers were later criticised by True (1903), 

 who expressed the opinion that Phoccena or Tursio alhiventris 

 (Perez, MSS.) Philippi, 1893, 1896, is a synonym of G. eutrojna, 

 and that Tursio platyrrJdnus Philippi, 1896, is probably the 

 same species. Tursio 1 jxmopeX Philippi, 1896, was not thought 

 by True to be referable to Cephalorliynchus., but it seems possible 

 that it may also belong to this genus. 



The external characters have been described in Cejjhalorhynchus 

 heavisidei, C. albifrons, G. hectori, and G. albiventris. G. etctropia, 

 G. platyrrhinus, ? C. panopte, and ? G. chiloensis are known from 

 cranial characters alone. 



The British Museum possesses the type-specimens of G. eit- 

 tropia§ and C. heavisidei. The skull of the latter was inside the 

 mounted skin when Flower wrote his revision of the Delphinidfe 

 in 1883. It has since been removed, and although defective 

 in the occipital region, it is otherwise in good condition. 

 The following table gives measurements of the skulls in the 

 Museum : — 



* The measurement recorded by Moreno is 138 cm., and tliat given bv Bruce is 

 132-2 cm. 



t The distances between the apertures were in each case measured from their 

 middle points. 



X Philippi (1901) later described a new Dolphin, Tursio ? chiloensis, from Chili, 

 which he stated to have resemblances to T. panope. 



§ Figured bj' Gray 1846, pi. xxxiv. figs. 1, 2; see also Gray, 1866, p. 262. 



