65 
as it should be, in those animals. “Umgekehrt kommt denjenigen 
Wirbeltieren, die noch einen oder mehrere hinter dem Vagus das Cranium 
verlassende Nerven besitzen, auch ganz constant ein Occipitale superius 
zu; in diese Kategorie gehören die Amnioten und die größte Mehrzahl 
der Knochenfische.” If I was right in my conclusion (No. 4) that the 
two posterior, partly assimilated occipital vetebrae of Amia are re- 
presented in the first two free vertebrae of Scomber, it is evident that 
SAGEMEHL’S proposition can not be wholly correct, a supraoccipital 
not being found in amia. It is also to be recalled that both van WIsHE 
and CoLLINGE have stated that the supratemporal commissure of Aci- 
penser traverses a median, dermal supraoccipital, instead of lying, as 
SAGEMEHL states, anterior to the most anterior, median, dorsal “Haut- 
schild”; that WIEDERSHEIM and Huxtey both call one of the bones of 
Lepidosiren a supraoccipital; and that Fritsch says (No. 15, Bd. II, 
p. 68) that in fossil Dipnoi there is a median dermo-occipital. 
According to VROLIK (No. 33) the supraoccipital of Teleosts is a 
bone developed on or in the cartilage of the chondrocranium, in 
relation to the point of attachment of muscles or ligaments, and that, 
in its origin, it is in no way related to the lateral sensory canals. It is 
however to be noted that it seems to be associated with, if not related 
to, a but slightly developed extrascapular; and that, with the reduc- 
tion of this latter bone, and naturally also of the canal that traverses 
it, the middle head line of pit organs may be found relatively much 
more strongly developed than it is in Amia. Thus, in both the 
Characinidae and Cyprinidae the extrascapular is said by SAGEMEHL 
(Nos. 28 and 29) to be reduced to a little bony scale lying at the 
hind edge of the squamosal, and in all these fishes there is, in the 
parietals, that is, in the position of middle head line of pit organs, 
a canal, called by SAGEMEHL the supratemporal commissure but said 
by him not to be the homologue of the one so-named in Amia. 
In Scomber, on the contrary, although the extrascapular is an 
exceedingly delicate scale-like bone lying in the integument posterior 
to the bones of the skull proper, the middle head line of pit organs 
is not especially important. The same relations between bone and 
pit line exist in Gadus, according to CoLe’s descriptions (No 9), and 
there are said to be, in this fish, four supratemporal bones. The same 
relations will probably be found to exist in Salmo, where PARKER says 
(No. 24, p. 99) there are no conspicuous supratemporals; in Alepo- 
cephalus where GEGENBAUR probably describes that bone in the little 
superficial bone already once referred to; and in Amiurus where I 
can not find that McMurricu (No 23) even describes the bone. 
Anat, Anz. XVI. Aufsätze. 5 
