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KAMAKICHI KISHTNOUYE: 
with a well developed occipital crest. Tire bone is bounded in front by the 
frontals, and laterally by the parietals, epiotics, and sometimes by the 
exoccipitals as well. The posterior part of the bone gradually converges, and lies 
upon the median suture of the epiotics. The posterior slender portion is often 
extended over the suture of the exoccipitals. This bone has little characteristics 
in different families. 
The parietals are paired flat bones on both sides of the supraoccipital, and 
rest on the sutural lines between the supraoccipital, sphenotics, epiotics and 
sometimes pterotics, taking almost no part in the formation of the roof of the 
brain cavity. The parietals are surrounded in front by frontals, on the outer side 
by the pterotics, on the inner side by the supraoccipital, and behind by the 
epiotics. The parietals are rather small, each with a high, longitudinal crest 
on the dorsal surface. The crest forms a part of the temporal crest, and is 
continuous to the crest on the frontals in front, and to the epiotic process 
behind. In the Scombridae the parietals are provided with two crests. In the 
Cybiidæ the parietals are generally separated from the pterotics. In the 
Thunnidæ also the parietals do not unite with the pterotics, at most some¬ 
times touching with a corner above the sphenotics. In the Katsuwonidæ 
the parietals are united to the pterotics at the outer posterior side, and in 
the genus Auxin the whole outer side of the former bone is bordered by the 
latter, as in this genus the sphenotics do not appear at the dorsal surface of 
the skull. 
The sphenotics form a part of the lateral wall of the optic lobe, and at 
the same time a part of the dorsal wall of the optic cavity, externally 
they are a part of the articulating facet for the anterior head of the 
liyomandibular, moreover forming the postorbital ridge. The sphenotics are 
bounded externally by the frontals, alisphenoids, prootics, pterotics, parietals, and 
epiotics, and internally by frontals, alisphenoids, prootics, supraoccipital, and 
sometimes epiotics. In Bastrelliger the parietals and pterotics are also found 
round the sphenotics. The sphenotics are generally seen at the dorsal side of 
the skull, between the pterotics and parietals. In the Scombridæ the sphenotics 
are found at the dorsal, external side of the cranium, between the pterotic 
crests. The internal concavity of these bones is subdivided by a septum. In 
the Cybiidæ the sphenotics are more or less flattened bones and form a very 
