NO. 1552. NOTES ON MALAYAN PORCUPINES— LYON. 591 



Measureine7its. — See table, page 593. 



Specimens examined. —Two, skin and skull of nearly adult male from 

 Mount Salikan, Borneo, and the skeleton of an adult from British 

 North Borneo. 



TRICHYS MACROTIS Miller. 



1903. Trichys mncrotis Miller, Proc. U. 8. Nat. Mus., XXVI, p. 469, February 

 3, 1903. Type-locality: Tapanuli Bay, west coast of Sumatra. 



1905. Trichys macrotis, Willink, Natuurkundig Tijdschrift Nederlaudsch-Iudie, 

 LXV, p. 268. 



Dlsfrihatum.. — Sumatra. 



Type.Skm and skull of adult female, collected at Tapanuli Bay, 

 west coast of Sumatra, February 20, il»U2, by Dr. W, L. Abbott. 

 Orioinal No. 1,555. 



I)i(Ujm>st'iC chdracters. — Like TrlcJii/x H]>ura from Borneo, ))ut with 

 longer cars, more angled hanudai's, and smaller lachrymid bone. 



Color. — The color of T/'/ehi/s nidcroti.s differs in no way from that of 

 T. lipara. 



Ears. — The ears in Trlclnjx nidcrofix are nuich longer than the}" are 

 in T. J/piir<(^ and tiie tips broader and more rounded. Length of ear 

 from meatus in the type of T. nnierotls., 28 mm., in T. Ujfiira, Cat. No. 

 S31>-10, from Borneo, 18 mm. 



Sh'ul/. — The skull closely resembles that of Trichyx lipiira.. ])ut the 

 hamular process of the pterygoid bone has a more pronounced bend or 

 angle on its inferior aspect, and the tip, instead of ending- in a point 

 barely in contact with the auditid bulla, is consklerably thickened and 

 generally in contact with the bulla. The lachrymal bone is apparently 

 nuich longer in tlic; Bornean aiumal than in T. macrotis.^ although in 

 many s[)ecimens of the latter species the sutures are so obliterated as 

 to render it impossible to determine its exact size. Greatest length of 

 the lachrymal bone in the two Bornean skulls, 8 and 1* mm. respec- 

 tivel}', in four Sumatran skulls, 1 to 5.5 nmi. 



Measurements. — See table page 593. 



Specimens examined. — Seven, 5 from Tapanuli Bay and 2 from Aru 

 Bay, Sumatra. 



RELATIONSHIPS OF THE FOUR GENERA OF MALAYAN PORCUPINES. 



The most primitive and unrelated to the others of the Malayan por- 

 cui)ines is the genus Trh-htjx. Externally Trlclnjs and Afhernrus are 

 nuu'h alike, but the terminal tail l)ristles of Trlchijs are peculiar and 

 bear no distinct relation to those of Afheriirns or to the other genera. 

 Both Trichys and AtJh rurns have ro(»ted molars, while the molars in 

 the other two genera are rootless. Osteologically 7)-lchi/x shows many 

 peculiarities not possessed by the other genera, sudi as the general- 

 ized form of the skull, large number of dorsal vertebrjc and narrowed 

 Proc. N. M. vol. xxxii— 07 38 



