158 ERIK A : SON STENSIO 
terminology. That this is the case may already be clear to some extent from what has 
been said above. But in order to obtain a somewhat deeper insight into the question 
it is necessary to discuss here briefly the different views that have so far been put 
forward about certain homologues of the so-called pterotic («squamosal») and opisthotic 
(intercalar) of the Teleostei. 
Schmid-Monnard (i 883 , pp. 109 —m, 116—123, 127—134) is of the opinion that 
he found the «squamosal» (pterotic) of the Teleostei, to be composed of three or four 
components. These components are said to arise separately during the ontogenetical 
development and are as follows: 
1) a sensory canal component, which arises round the sensory canal; 
2) a component of cartilage bone, which is formed round the external semicircular 
canal and occurs regularly together with the former; 
3 ) in addition a fibrous component, formed in connection with the tendons that 
are attached on the posterior part of the bone in question, and finally 
4) a fibro-cartilag-inous component appearing in relation to the articulating surface 
for the hyomandibula. — Components 3 and 4, however are said to be inconstant. 
Schmid-Monnard’s view is followed in essentials by Allis (1899). Thus the latter 
describes in Scomber three of the above-mentioned components. Only the fibro-cartilaginous 
one is stated not to be present. With regard to the relations of the components in the 
«squamosal» (pterotic) in fishes in general Allis speaks as follows in 1899 (p. 59): 
«We thus see that the squamosal of fishes is composed of a canal component and a 
deeper-lying component which may be. either a so-called membrane bone, or such a 
bone fused with a so-called primary ossification. The primary ossification may be wholly 
wanting, and perhaps the canal component too. Furthermore the canal component may 
be found entirely separate from the underlying bone, may be found fused simply with 
an underlying membrane component or may be found fused with such a component 
and with a so-called primary ossification, which latter ossification, alone, is traversed 
by the external semicircular canal. The canal component apparently always united 
with the underlying dermal bone may as a so-called dermal bone be fused with other 
adjoining dermal bones; while the primary ossification may be fused with other primary 
ossifications (Ctenodus) or with such ossifications and the intercalar (Polypterus). It is the 
primary part of the bone and not its «Deckknochenteil» that gives articulation to the 
hyomandibula». 
Sagemehl (1885, p. 59; 1891, p. 507) describes in the Teleostei two components in 
the «squamosal» (pterotic), a dermal and a primary one. 
Turning to the opisthotic we find that Huxley (1864, 1871) saw in it an integral 
ossification in the capsula auditiva. 
Sagemehl (1884, pp. 191 —192; 1885, pp. 45 — -46; 1891, pp. 556—-558) also followed 
Huxley inasmuch as he considered the opistotic as a bone that was originally developed 
phylogenetically in the cartilage of the capsula auditiva. Afterwards, according to his 
view, a secondary component could in certain cases be added to it, a fibrous ossification, 
which had arisen in the ligament fastening the suprascapular process to it. Further, 
according to his view, a partial or total reduction of the primary part took place in 
the Teleostei, so that the fibrous component alone is present in these. The reduction 
