ON THE ANATOMY OF THE NORTHERN BELUGA. 411 
None of the fibres of this muscle are inserted into the hyoid bone. In this 
respect Beluga differs from G'lobiocephalus, in which, according to Dr Murtz,* 
they are inserted into the cerato-hyal and basi-hyal bones. A similar arrange- 
ment to that above described obtains, according to CARTE and MACALISTER,t in 
Balenoptera rostrata. 
Stylo-glossus Muscle is narrow and riband-like, and arises from the junction 
of the upper and middle thirds of the stylo-hyal bone. It passes obliquely 
forward and downward, and is inserted into the lateral border of the tongue 
opposite the junction of the anterior and middle thirds of that organ. It rests 
upon the superficial surface of the next muscle. 
In Globiocephalus this muscle appears to be much larger than in Beluga, and 
arises from the whole length of the stylo-hyal bone. The identification of this 
muscle with the stylo-glossus, described by Carte and Macatister{ in Balenop- 
tera, is somewhat difficult. These authors describe it as lying superficial to 
all the other lingual muscles ; whereas, in Beluga, it was concealed by the 
mylo-hyoid. As, however, in Balenoptera the last-named muscle appears to be 
narrower than in Beluga, it is not improbable that the difference in relative 
position of the stylo-glossus in the two species may be referable to this fact. 
Upon this hypothesis, the arrangement of the stylo-glossus is essentially the 
same in both. 
Hyo-glossus Muscle arises from the transverse ridge on the lower surface of 
the basi-hyal bone under cover of the genio-hyoid muscle, as well as from the 
whole length of the stylo-hyal, and is inserted into the anterior two-thirds of the 
lateral margin of the tongue. It is placed between the stylo-glossus on the 
outer and the genio-glossus on its inner side. : 
The arrangement of this muscle seems almost identical with that described 
by Stanntus § in the porpoise, and differs from that of Globiocephalus,|| in which 
the muscle consists of ¢wo distinct portions, one of which arises from the stylo- 
hyal bone. In Balwnoptera rostrata the origin of the hyo-glossus is confined to 
the thyro-hyal element. 
Palato-glossus Muscle measures 5 inches in breadth. The fibres pass from 
the palate to the side of the tongue, where they intermix with the other muscles 
of that organ. 
This arrangement is similar to that described by Dr Mure! in Gilobiocephalus. 
A muscle, which is difficult to identify with any of those described by Dr 
Mourie** in Globiocephalus, or by Carte and Macauistertt in Balenoptera, 
arises under cover of the hyo-glossus, from which, however, it is quite distinct 
and easily separable. It is narrow and riband-like, and arises from the free 
extremity of the thyro-hyal bone. It passes forward, crossing the outer side of 
. 252. +1. pe 231. + Lp, 231. § Xa py S 
|| IL. p. 252. § IL p. 254, ** TI, tt 
