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of bone that unites the dorsal and anterior rays, and the anterior pore of the main infraorbital canal 

 lies at the outer end of this ray, there opening on the external surface of the web of bone, close to its 

 dorso-anterior edge. On the internal surface of the bone, opposite or slightly anterior to this latero- 

 sensory opening, a stout ligament has its origin, and, running ventro-mesially, is inserted on the 

 lateral surface of the dorsal edge of the maxillary process of the palatine, opposite and immediately 

 anterior to the surface of insertion of the rostro-palatine ligament. On the ventral edge of the anterior 

 ray of the bone, usually close to its base, and hence between it and the anterior one of the two ventral 

 spines of the bone, is the opening of the second primary tube of the infraorbital canal; and on the 

 ventro-posterior edge of the anterior ventral spine, is the opening of the third primary tube of the 

 same canal. On the posterior edge of the posterior ventral spine, or on the ventral edge of the pos- 

 terior ray of the bone, the position varying slightly, is the opening of the fourth tube; this tube 

 lying between the lachrymal and the next posterior bone of the series. Along the internal surface 

 of the posterior ray, the main infraorbital canal passes from the lachrymal into the second bone of 

 the chain. The rays of the lachrymal bone thus, all but one, have relations to the primary tubes 

 of the latero-sensory System. The bone lodges three sense organs of the infraorbital line. 



The second infraorbital bone, is, in position, a first suborbital bone. It is an elongated bone, 

 traversed by the main infraorbital canal, and has primary tubes of the line at either end. It lodges 

 a single infraorbital sense organ and hence is a single latero-sensory skeletal unit. A short spine 

 arises near the hind edge of the bone, and projects backward above the fifth infraorbital pore. This 

 spine is hardly noticeable in young specimens of Scorpaena scrofa, or in either young or adult 

 specimens of Scorpaena porcus. 



The third infraorbital, or second suborbital, is, as Gill ('88) says, „hypertrophied and devel- 

 oped as a stay impinging on the anterior wall of the preopercular". It abuts against, and is firmly 

 bound by tissue to, a depressed line on the anterior surface of the outer edge of a strongly developed 

 ridge on the outer surface of the preopercular, opposite the base of the largest and most dorsal pre- 

 opercular spine. The bone is convex externally and concave internally, and in the middle line of 

 its external surface there is a longitudinal ridge which marks the position of the enclosed latero- 

 sensory canal. Near the posterior end of this ridge, two primary tubes lead from the canal to the 

 outer surface of the bone, one on the ventral surface of the ridge, and the other, slightly posterior 

 to it, on the dorsal surface of the ridge; these tubes being, respectively, the 6 th. and 7 th. primary 

 tubes of the line. The bone lodges two infraorbital sense organs. A short spine projects backward 

 above the seventh infraorbital pore, this spine, like the one on the first suborbital, being unimportant 

 in young specimens and in Scorpaena porcus. 



The postorbital bone is a small semi-cylindrical piece of bone that lies in the dermis that 

 forms the hind margin of the orbit, about midway between the dorsal edge of the third infraorbital 

 bone and the postorbital corner of the skull. It lodges a single latero-sensory organ, and is developed 

 in relation to that organ. 



3. SUSPENSOR1AL APPARATUS AND MANDIBLE. 



The hyomandibular, symplectic, preopercular and palato-quadrate are all united or firmly 

 bound together, and form a single piece which articulates with the skull at its anterior and posterior 

 ends and bears the mandible. 



