of the Genus Martes. 291 
saying, from an examination of the above specimens, that the yellow- 
breasted specimen is merely the young of the other ; and that the Com- 
mon Marten retains a yellow tinge on that part until after the first, 
or perhaps until after the second winter. My yellow-breasted speci- 
men had been obtained in September, and was not, I should think, 
from the state of ossification, an animal born during the foregoing 
summer ; the other specimens were all procured during winter, are 
all larger, and have the colouring on the breast not nearly so deep 
as in the one just mentioned. Had I not, however, seen a cranium 
in an intermediate state, I should certainly have supposed that the 
skeletons were those of two distinct species. 
I do not, however, by any means intend to affirm that no second 
species exists in the British Isles, as my specimens were all obtained 
from a limited district in North Wales, but nevertheless presenting 
all the characteristics of the supposed British species. 
The numbering of the vertebre and ribs in both skeletons are the 
same ; but I give them here for the sake of offering other persons the 
opportunity of comparing them with any skeletons that they may have 
belonging to the genus. 
Cer. 7, dor. 14, lum. 6, lac. 7, caud. 15, ribs 14 pair. 
The form of the different bones, with the exception of some of 
those composing the crania, do not present any remarkable differ. 
ences ; those, however, of the smaller skeleton present many marks 
of immaturity. The following admeasurements will show the dis- 
parity in size. 
Larger skeleton, Smaller skeleton, 
or adult. or young. 
Inches. Inches. 
EIRCOR TIDIE 6. on gp oe wrens ss 3545 3 
DETOUR, fc Sc vy cig 355 2,9, 
BING OG Gc bcs a eee t 259, 2} 
Peer os. ree 254 
(hia dS gai laa 1% 155 
Meet GittO.... 5.22. oe. Lh 14 
Length of cranium...... ge sine hee 335 3 
Meneetne 06 CIELO. os oo. iw mens 2 13, 
Beeeetas OF PEWVIS, 65. ik. oe 2555 255 
Breadth of ditto, at acetabular cavity 1,4, 15 
In the cranium of the younger specimen, the tuberose process to 
which the ligamentum nuche is attached appears the most promi- 
nent, and the crest over the vertex, on which the temporal muscles 
arise, is narrower than in the adult. The greater degree of promi- 
nence in the tuberose process in the young, may be explained by 
the crest running from it over the vertex as it becomes broader, 
filling up the indentation on each side; thus this apparently greater 
degree of prominence merely proceeds from an incomplete state 
of ossification in the surrounding parts. 
The next most striking point of difference in the cranium, is that 
u 2 
