62 
scapular. It is usually called the supratemporal by English writers, 
and Srtannıus is said to have first given the name extrascapular to it. 
to distinguish it from a bone that lies lateral to the squamosal and 
is also called a supratemporal. This latter supratemporal bone is. 
shown by PARKER in Salmo (No. 24, Pl. VI, Fig. 1), and is unquestion- 
ably traversed by, and developed in relation to, the dorsal end of 
the preoperculo-mandibular lateral canal. The extrascapular of Tele- 
osts may be found as a series of bones, as in the Cod, Plaice, and 
Turbot (No. 31), and it or they probably always lodge, as in Amia, 
not only a part of the main infraorbital lateral canal, but also a supra- 
temporal branch of that canal which is the homologue of one half of 
the crosscommissure of Amia. A part of the bone, or of the series 
of bones, or a part of the canal by which it or they are traversed, 
seems, as stated above, to always lie superficial to the exoccipitale. 
In Polypterus there are, on each side of the supratemporal region 
of the head, three bones called by Traquarr (No. 32) the supra- 
temporals; andthese three bones combined are usually considered as the: 
homologue of the single extrascapular of Amia. The lateral one of 
the three bones of Polyterus is said by TRAQUAIR to lodge a section 
of the main infraorbital canal, and from this section a branch canal 
arises, which, traversing the other two bones, forms the supratemporal 
crosscommissure of the fish. This commissure is usually considered 
as, and in all probability is, the homologue of the one in Amia, but 
its innervation is not yet definitely known, POLLARD simply indicating, 
in a table (No. 26, p. 398), that it is innervated by a branch of the 
vagus. According to COLLINGE (No. 10) the main infraorbital canal 
of Polypterus traverses two of the supratemporal bones, instead of 
only one of them, the crosscommissure lying, however, partly in each 
of the three bones, as TRAQUAIR states. The commissure, and one, 
at least, of the three bones that lodge it, lie superficial to the epiotic: 
portion of the so-called opisthotic bone of the fish. By Hux ey (No. 18) 
the most lateral bone of the series was considered as an epiotic, the 
mesial one being called a supraoccipital, these two bones thus being 
homologised with the correspondingly named bones in the Stegocephali, 
but the middle one of the three being left unaccounted for. 
In Lepidosteus, CoLLınGE (No. 11) states that the supratemporal: 
commissure traverses, on each side, a supratemporal and a dermo- 
occipital bone. The dermo-occipital is not shown as a separate bone 
in PArker’s figure of the fish (No. 25, Pl. 37), the space between the: 
supratemporals, that should apparently be occupied by the dermo- 
occipitals, being occupied by the hind ends of the parietals. Accord- 
