— 61 — 



face of tlie latter bone. The mesial process of the exoccijntal of Scorpaena is, accordingly, a definite 

 part of the cranial wall and not simply an ossification of the dura mater, as Sagemehl considered 

 it to be ('84 b, p^ 85). That part of the process that, in the Characinidae and Cyprinidae, is said by 

 Sagemehl to roof the cävum sinus imparis may however be such an ossification; for this cavum lies 

 in the cranial cavity itself, and not in the walls of that cavity, as the saccular recess does. The true 

 internal, or cerebral surface of these two occipital bones of Scorpaena is accordingh^ formed by the 

 mesial processes of the exoccipitals and by that small portion of the dorsal surface of the basioccipital 

 that lies between those processes. The nervus glossopharyngeus first perforates the mesial, mem- 

 branous wall of the labyrinth recess and then the outer, bony wall of the recess, as in Amia, traversing, 

 in its'course, a space that is hollowed out of the cranial wall to receive the ear and the ganglion of 

 the nervus acusticus. 



The anterior portion of the cranial cavity of Scorpaena is enclosed between the alisphenoids 

 and the ventral flange-like processes of the frontals, and does not, in the adult, lodge any portion 

 of the brain, the brain being small, relatively to the cranial cavity, and its anterior end reaching, 

 approximately, only to the level of the hind edge of the basisphenoid. This part of the cranial cavity, 

 in the dried skull, opens ventrally, by a relatively long and narrow median opening, into the hind 

 end of the orbit, and this opening, bounded posteriorly by the basisphenoid, is the orbital opening 

 öf the brain case. In the recent state it is closed by the flaring dorso-posterior edge of the mem- 

 branous posterior portion of the interorbital septum. Posterior to the hind edge of the basisphenoid, 

 and extending approximately to the hind edge of the proötics, there is, in the recent state, when 

 the brain is removed, a large, nearly round, pit-like depression, formed in the fatty and connective 

 tissues that cover the floor of the cavity. This depression lodges the hypoaria, and has, near the 

 anterior edge of its floor, a small saucer-like depression which lodges the pituitary body and overlies 

 the pituitary opening of the brain case. 



2 INFRAORBITAL CHAIN OF BONES. 



The infraorbital bones are the three so-called suborbital bones of current descriptions, and 

 a small postorbital bone, which latter bone has, so far as I can find, never been described. 

 > - ■ The three so-called suborbital bones are, as is well known, firmly bound together to form 

 a Single rigid piece which extends backward across the cheek and abuts against and is firmly bound 

 to the outer surface of the preopercular. The anterior one of these three bones, which I shall call 

 the lachrymal, is an irregulär five or six rayed bone, and is called by both Günther ('60) and Boulenger 

 ('04) the preorbital. The several rays of this bone are of varying and unequal proportions, and their 

 bases are connected, excepting between the dorsal and posterior rays, by thin webs of bone in which 

 there may be additional smaller rays. The dorsal ray is a thick stout process, which is concave on 

 its dorsal edge and there articulates with the large articular surface on the outer end of the horizontal 

 arm of the ectethmoid. The anterior ray is a pointed process, and rests upon and is strongly bound 

 by ligamentous tissue to the lateral (distal) portion of the dorsal surface of the ligamentary process 

 of the maxillary. The posterior ray is a sharp or rounded process which fits against, and is rigidly 

 bound to, the outer surface of the anterior end of the second bone of the series. Two of the remaining 

 rays form two of the sharp spines characteristic of the fish, the one directed ventrally and the other 

 antero-ventrally, from the ventral edge of the bone. The sixth ray, when present, lies in the web 



