— 114 — 



large one, with one or two adjoining eminences rather than spines. Near the bind edge of the orbit 

 there is, in medium-sized specimens, a short and somewhat blimt spine, which is not evident in the 

 large specimens. The only other spines found on the head of the fish are two spines, or eminences, 

 on the hind edge of the preopercular, and two spines on the opercular; only one of these latter spines 

 showing on the oiiter surface of the fresh head. 



Between the orbits, in medium-sized specimens, the dorsal surface of the skull is deeply con- 

 cave transversely, while in large specimens it is much less so; and in all specimens there is here no 

 longitudinal ridge, on either side, to mark, as in Scorpaena, the course of the supraorbital latero- 

 sensory canal. The crown of the head is flat, the subquadrangular groove on the occiput, so charac- 

 teristic of the Scorpaenidae, being slightly indicated in my medium-sized specimens by two little 

 tuberculated and longitudinal ridges, one on either side, on the dorsal surface of the parieto-extra- 

 scapular bone. These ridges are not evidemt in the large specimens. The preorbital portion of the 

 skull is relatively long, low and broad, the casque-like portion of its dorsal surface here being convex 

 transversely and having straight lateral edges which converge but slightly forward; the casque being 

 two-thirds or even three-fourths as wide at its deeply concave anterior end as it is at the anterior 

 edges of the orbits. 



The curved anterior ends of the lachrymals project forward and mesially, on either side, beyond 

 the anterior end of the skull, and, with the concave anterior end of the casque, nearly enclose a sub- 

 circular space in which the rostral lies. The anterior edge of the lachrymal is, in all my specimens, 

 serrate rather than being, as stated by Günther ('60), furnished with prominent spines. 



The dorsal surface of the casque is formed by the nasals, mesethmoid, ectethmoids, frontals, 

 postfrontals, pterotics, parieto-extrascapulars, lateral extrascapulars and suprascapulars, and also 

 by a small portion of the sphenotic which comes to the level of the other bones and presents the same 

 granulated appearance. The supraoccijsital and epiotics are almost entirely, or even entirely covered 

 by the overlying frontals, parieto-extrascapulars and suprascapulars. 



The mesethmoid and ectethmoids come, as just above stated, to the level of the dorsal surface 

 of the other bones that form the casque-like portion of the skull, and, having the same surface mark- 

 ings as those other bones, they form wit,h them a uniform and continuous surface. They each contain 

 the two somewhat different components, dermo-perichondrial and endosteal, referred to when des- 

 cribing these same bones in Scorpaena; but here, in Trigla, the dermal portion of the dermo-peri- 

 chondrial component is much more important. 



The MESETHMOID, as seen on the dorsal surface of the skull, is sometimes, as Günther 

 ('60) says of the corresponding bone in Trigla gurnardus, a sexangular bone, once and a half as long 

 as broad; but the two posterior Corners of the bone thus described, are usually replaced, in medium- 

 sized sj^ecimens, by a single point, the bone then being pentangular. The outer surface of the bone 

 is marked by granulated ridges that all converge toward the central point of the bone, and in the 

 substance of the bone, and converging toward this same point, there are tapering Spaces. These 

 Spaces lie in the dermal portion of the bone, between the dense outer surface of this portion of the 

 bone and the thin perichondrial layer, and the concave anterior edge of the bone is honeycombed by 

 the openings of the Spaces. This anterior edge of the dermal portion of the bone is grooved, the dense 

 superficial layer of the bone projecting eaves-like above the deeper perichondrial layer. This latter 

 layer extends anteriorly slightly beyond the dermal layer, and is there bounded, in the niiddle line, 



