344 BONES OF LOPHIUS PISCATORIUS — MORROW. 
will show you that this is essential to the support of part of the 
opercular apparatus. On their interior inferior terminations there 
are no prominent surfaces for the articulation of the stylohyals 
but they rest in a groove and have thin ligamentous attachment. 
24. & 25. The pterygoids and entopterygoids are represented 
in the Lophius by single bones, one on each side, which are of an 
irregular oval form at their posterior, assuming a subtriangular 
shape at their anterior extremities, and have small processes 
which connect them with the quadrate bones. They are very 
thin membrane bones, and the portion below their processes may 
be taken to represent the pterygoids, for to them are attached 
primarily the palatines. The upper portion of these bones 
will represent the entopterygoids. 
26. The quadrates, as well as the other bones connected with 
them, are, for such large fishes, very delicate. The condyles, for 
their union with the articularies, are exceedingly small, and 
appear on the inner sides of the bones ; rising from them are 
ridges, folded posteriorly, against which abut the preopercular 
bones: below the condyles, extending posteriorly and down- 
wards, at a small angle, these bones present somewhat broad sur- 
faces, having at their posterior edges sharp points or spines, which, 
when the fish closes its mouth, are easily seen. 
27. The metapterygoids are very delicate fan-like plates, 
having narrow thickened edges, which, at their upper arms con- 
nect with the hyomandibulars nearly in their centres. These 
edges are a little wider, and have projecting processes for the 
attachment of the ligaments which tie them to the prefrontals. 
28. The opercula are long and narrow, nearly straight, bones, 
which articulate with the hyomandibulars just below their junc- 
tion with the mastoids and prefrontals, they are almost flat on 
their inner, and have ridges on their outer surfaces ; beginning 
at the centre of their superior and terminating at their anterior 
edges on their inferior extremities, these ridges support the 
subopercula; at their superior extremities, they throw out pos- 
teriorly each a long slender fin-like ray. 
30. The preopercula are small and narrow curved bones, angu- 
lar at their posterior edges, having ridges upon them which show 
