240 MR. R. COLLETT ON HYBRID GROUSE. (Apr. 20, 
also leaves and twigs of different plants, procured principally on the 
marshes, and occasionally (like Arctostaphylos alpina) from the true 
alpine district ; likewise from various berries, and occasionally from 
birch-catkins. Several of these articles of nourishment form the 
food of Blackgame; nevertheless it is certain that most of them 
come from marshy places, from which it must be assumed that its 
diet most resembles that of the Willow-Grouse, 
Skeleton. 
In a skeleton of a male from Saltdalen (Nordland) the measure- 
ments are as follows :— 
rillim. 
Length of the skull (bill included) .......... 63 
Greatest breadth of the skull .............. 28 
Lenpth of Seapula.. a.m. aan» shay =. iS gee ee 
Diemer Ge OL, ENMMIEE US ona dn ne 1s > eo ce 
NSN UR GE PRUNES coos owen sn cna ia acne ED 
Length of ulna... .....2..--20 a: suena aA 
Length of os coracoideum .............--- 55 
Length of metacarpus Il. .... Ae. 
Length of the two phalanges of digitus 11 Eloy ispape Se 
Length of furcula (to the aoe of the flee 66 
Leneth of sternum..... A Ss iy 2) ae 
Greatest height of crista tee 34 
Length of pelvis (to the first caudal ek aie << aged 
Greatest breadth of pelvis (across ossa ischii). . 57 
DEE Ge Ce ga A ee Te eee PA eh! 
Length of fibia” . .. 2.5. - 2s puto AR Ae 21 
Length OUGHT STS: oct fom nicl eho i total ek ta ae ener ee 45 
Length of middle toe (claw not included) ...... 45 
As the skeletons of the two parents, Lagopus albus and Tetrao 
tetriz, resemble each other so nearly that, apart from their difference 
cf size, it would be difficult to find out the most trifling characteristic, 
this hybrid hardly has one distinctive feature in the structure of its 
skeleton beyond its difference in size. 
Christiania, March 1886. 
EXPLANATION OF THE PLATES. 
Puate XXI. 
Hybrid between Lagopus albus and Tetrao tetriz. 
Fig. 1. Male in winter dress. 
Fig. 2. Female in winter dress. 
Prate XXII. 
Hybrid between Lagopus albus and Tetrao tetriz. 
Fig. 1. Young male in early autumn dress. 
Fig. 2. Young male in late autumn dress. 
