106 EINAR LONNBERG, MAMMALS COLLECTED BY THE SWEDISH ZOOLOGICAL EXPEDITION ETC. 
galeata-group with long nasals which as a rule have a great relative breadth also in 
front, and the southern africe-australis-group with shorter nasals which are much 
narrower in front than behind. 
The Porcupines obtained by this Expedition belong, as could be expected, to 
the former group and to Hystrix galeata, which species, however, has been subdivided 
into some geographical subspecies by the present writer’ and Frerp. Mixer.’ Of 
these subspecies H. g. ambigua LONNBERG is easily recognized on the shape and 
proportions of its nasals, the breadth of which at the front end of the nasopremaxil- 
lary suture is only 57 °/o of their breadth at the posterior end of the same suture ete. 
Ferp. Miiier has named not less than three new subspecies of H. galeata. 
In doing so he lays great stress on the fact that the skull of the type of H. 
galeata THomMaAS (which was a young or semiadult specimen in which the last molar 
is not yet in use) has greater posterior interorbital width (at rudimentary postorbital 
processes) than anterior interorbital width (at edge of lacrymals). MULLER regards 
this as such a valuable characteristic that he divides the subspecies of H. galeata 
>in 2 Gruppen» — — »einmal in solche, deren grésste Frontalbreite hinten, an dem 
rudimentaren processus postorbitalis liegt, und sodann in solche bei denen die Breite 
der Frontalia vorne, an der Wurzel des Lacrymale, am gréssten ist.» To the first 
group belongs (the type of) Hystrix galeata Tuomas, to the second the already men- 
tioned H. g. ambiqua, and MULuLER’s »H. g. conradsi», »H. g. lademanni», and »H, g. 
lénnbergi>. Concerning the three latter not much information is given. H. g. con- 
radsi is said to have the width of processus nasalis premaxillaris 12—14 mm., and 
the thickness of arcus zygomaticus maxillaris 3,,—4 mm., while the corresponding 
measurements of H. g. lademanni are 16—16,5 and 7 mm. respectively. With regard 
to H. g. lénnbergi the reader obtains no other information than about those points 
by which it differs from H. g. ambigua, but not how it is to be distinguished from 
H. g. conradsi, and H. g. lademanni, while the difference from the typical H. galeata 
shall consist in the anterior interorbital breadth being smaller than the posterior. 
The question is now whether these interorbital measurements and the relation 
between them is constant or not? That the interorbital measurements themselves 
are not constant is easily ascertained by examination of some Hystrix galeata-skulls 
of different age. It appears also almost certain that the anterior interorbital width 
increases more with age than the posterior to judge from the general development 
of the skulls. In two specimens from Kilimanjaro, for instance, the anterior measure- 
ment is in the younger 69 mm. and in the older 75 mm. while the posterior mea- 
surements are resp. 67,7 and 71,5 mm. The difference between the two dimensions 
is thus in the younger only 1,3 mm. but in the older 3,5 mm.* I appears therefore 
probable that in still younger skulls this difference may decrease still more, or even 
be inverted. 
The variability of these dimensions has also been very plainly proved by Frrp. 
Mittier himself concerning the by him described H. stegmanni.* The difference 
Mammals. Schwed. Zool. Exp. nach dem Kilimandjaro und Meru. Upsala 1908, p. 29. . 
Sitzber. Ges. Naturforsch. Freunde. Berlin 1910 p. 314—315. 
% Arch. f. Naturgesch. 76 Jahrg. 1910. Bd. I, p. 182. 
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