388 
EDWARD PHELPS ALMS. 
attention to this, and explains it by saying that the corre- 
sponding muscle in Alytes, Rana, Pelobates, and Lepus is 
formed from the ventral end of the hyal myotome, and 
that this method of formation is probably the primitive one. 
The intermandibularis of all teleostoman embryos is said 
by Edgeworth (loc. cit. , p. 187) to form at first, with its fellow 
of the opposite side, a transverse muscle attached laterally to 
Meckel’s cartilage, and it is later said (loc. cit.,p. 202) that a 
comparison of the various forms of the muscle shows that 
this condition of a transverse sheet is the primitive one for 
the muscle. It is, however, immediately afterwards said that 
this condition of a transverse sheet persists (“ exists ”) only in 
Salmo. Edgeworth further says (loc. cit., p. 280) : “ (3) The 
intermandibularis anterior and posterior (the latter called 
* inferior geniohyoid ’ by Allis) of Amia are innervated by both 
the fifth and seventh (Allis). (4) The hyo-maxillaris of 
Teleostomi, developed in the hyoid segment, is in some, e. g. 
Menidia (Herrick), wholly innervated by the seventh ; whereas 
in others, e.g. Esox (Vetter), Salmo, its hinder part is inner- 
vated by the seventh and its fore part by the fifth ; and in 
Amia (Allis) it is innervated by the fifth and seventh.” 
These latter two statements would seem to imply that 
certain of the individual fibres of the muscles referred to in 
Amia were innervated at the same time by two different nerves, 
and that they were in process of losing their normal innerva- 
tion by the nerve of their segment of origin and secondarily 
acquiring an innervation by a nerve of another segment. If 
this be the meaning of the statements, the reference to Amia is 
unfortunate, and is apparently based on the literal acceptance 
of the heading of one of the sections of my work on that fish 
without any consideration of the accompanying text. That 
heading is (Allis, 1897, p. 559) : “ Muscles innervated by both 
the Trigeminus and Facialis,” which, literally accepted, might 
have the meaning that Edgeworth apparently gives to it. But 
in the text (loc. cit., p. 613) it is carefully explained that the 
muscles in question are innervated by branches of a nerve 
formed by the anastomosis of trigeminus and facialis branches 
