1885.] MR. R. COLLETT ON ECHIDNA ACANTHION. 153 



side, yet here mixed with normal hairs. At the hind margin of the 

 ear is found a thick patch of blackish hairs, as in the other species. 

 The belly is covered with hairs, longer or shorter, mixed with 

 flatfish bristles ; on the breast and lower side of the head there are, 

 as a rule, no bristles, but hairs only. 



Colour. — The dorsal spines are pale yellowish with black tips ; this 

 i)lack tip is very short in the longer spines, but broader in the 

 shorter ones, by which the longer get a clearer appearance than the 

 rest. In some specimens (but not in all) one or two of these spines 

 are entirely yellowish without black tips. In the shorter spines the 

 pale colour at their bases is almost hidden by the black. Thus, 

 contrary to E. aculeata, where all spines are equally coloured (yellow- 

 ish with short black tips), and iilnmst of the same length, E. acanthion 

 at a distance appears to be blackish with irregular series of long and 

 clearer-coloured spines. On the nape and the front the spines are 

 sometimes entirely black, sometimes yellowish, or particoloured. 



One of the specimens (No. 9) differs a little from the rest, the 

 longer spines here being almost black, like the shorter. This spe- 

 cimen, a full-grown femal^, therefore appears to be blackish with 

 a few yellowish spots. 



The colour of the belly is blackish brown, under the tail perfectly 

 black ; in some specimens a paler line may be observed on the outer 

 side of the legs. 



The young male (No. 1) is somewhat different from the rest, the 

 breast and throat being reddish brown, which colour also extends 

 itself along the inner side of the fore limbs, and can be traced also 

 on the hind limbs. An irregular black band crosses the throat from 

 the lower side of the ears. The belly is blackish brown, as in the 

 other specimens, and mixed with one or two yellowish spines. 



Skeleton. — In the young male, with a total length of 36.5 millim., 

 the skeleton is very far from being perfectly ossified. A large fonta- 

 nelle is found on the upper part of the os temporale ; in many of the 

 bones the different epipliyses are not yet grown together. There 

 are open sutures between the occipitals, and between the costcB 

 cervicales a.ud their vertebrte : the caput fetnoris is separate; the sacral 

 vertebrae are all separate, as well as the bones of the pelvis. On 

 the dorsal vertebrae the spinous processes are very cartilaginous ; 

 the same is the case with the upper margin of the scapula, of the 

 proe. olecranoides in thejibula, and at the ends of other bones. The 

 OS coracoideum is separate On the lower jaw the proc. coronoideus 

 ext. is still not developed. 



In an apparently almost full-grown female, with a total length of 

 425 millim., the sutures are still open around the os basioccipitale, 

 and the costce cervic. of the episfrophceus can still be separated when 

 slightly pressed, and the epiphyses both on the ulna and radius and 

 on thejibula and tibia may be easily parted \ 



' As mentioned above, all these parts are perfectly ossified in a specimen of 

 E. aculeata of tlie same size. 



