— 35 — 



single organ here, this showing that but a single extrascapular latero-sensory ossicle has here fused 

 with the parietal. 



The parietal spine on the dorsal surface of the parieto-extrascapular belongs to the anterior, 

 parietal part of the bone, the nuchal spine belonging to the posterior, extrascapular part. 



LATERAL EXTRASCAPULAR. 



The lateral extrascapular, the only independent extrascapular element there is in the skull of 

 Scorpaena, is a small plate-like bone that forms the larger part of the roof of the temporal fossa. 

 Its lateral edge rests upon the dorsal edge of the posterior process of the pterotic, and its posterior 

 edge upon the dorsal surface of the suprascapular. Its anterior and mesial edges are almost entirelv 

 enclosed in the reentrant angle in the postero-lateral corner of the parieto-extrascapular, from which 

 bone the extrascapular is separated by a narrow space bridged by fibrous tissue, this tissue holding 

 the extrascapular in place, forming part of the roof of the temporal fossa, and transmitting the supra- 

 temporal canal. The bone encloses a section of the main infraorbital latero-sensory canal, and also 

 the lateral portion of the supratemporal canal, lodging one sense organ of each of those canals. The 

 bone bears, on its hind edge, the anterior one of the two spines of the intermediate line. 



SUPRASCAPULAR. 



The suprascapular has a mesial, or epiotic, and an inferior, or opisthotic process, the epiotic 

 process forming the larger part of the bone and running insensibly into the body of the bone. The 

 body of the bone, which forms the lateral edge of the entire bone, encloses a short section of the main 

 infraorbital canal and lodges one organ of that canal. The epiotic process projects upward forward 

 and mesially, and rests upon the dorsal surface of the suprascapular process of the epiotic, fitting 

 closely into a narrow space between that bone, below, and the ventral surface of the projecting posterior 

 portion of the parieto-extrascapular above. The process of the suprascapular is firmly bound to each 

 of these two latter bones, its position relative to the posterior portion of the parieto-extrascapular 

 being that that it normally has to an extrascapular bone. The opisthotic process of the bone projects 

 ventro-antero-mesially and rests upon and is bound by tissue to a thickened portion of the hind edge 

 of the opisthotic. The process lies along, or internal to, the hind edge of the posterior process of the 

 pterotic, and forms the lateral wall of the posterior opening of the temporal fossa. On the internal 

 surface of the postero-lateral corner of the bone, close to its hind end, there is a small articular emi- 

 nence, and immediately antero-mesial to this eminence, an articular facet; the two surfaces articulat- 

 ing with corresponding surfaces on the dorso -anterior corner of the supraclavicular. The bone bears, 

 on its hind edge, two spines, one belonging to the lateral row of spines and the other to the intermediate 

 row. It is traversed by the main infraorbital latero-sensory canal and lodges a single organ of that line. 



SUPRACLAVICULAR. 



The supraclavicular is a triangulär bone. It lies along the outer surface of the clavicle, and 

 articulates, by two articular surfaces on its dorso-anterior corner, with the ventral surface of the 

 suprascapular. One of these two articular surfaces is an articular head that rises prominently from 

 the anterior end of the dorsal edge of the bone, the other being an articular facet that lies immediately 

 latero-posterior to the articular head. The dorsal edge of the bone, posterior to these articular surfaces, 



