OSTEOLOGY OF CAULARCHUS M.EANDRICUS (CIRARD). 2Q7 



The maxillary elements are very strong. The premaxillaries 

 send back long wide processes over the top of the head to be- 

 tween the eyes. Each maxillary bears a notch on its upper sur- 

 face for the reception of the edge of the premaxillary process. 

 The notch is some distance from the head of the maxillary and 

 allows it to meet its opposite fellow below the premaxillary proc- 

 esses, but viewed from above the maxillaries appear to be widely 

 separated. There is a depression in the upper surface of each 

 maxillary into which the palatine fits. 



The nasals are wide bones meeting on the median line, cover- 

 ing the anterior part of the premaxillary processes, and inter- 

 posed between the maxillaries above. 



THE BRANCHIAL AND HYOID BONES. 



The basibranchials are entirely absent, and the hypobranchials 

 are but slightly separated at the median line. The latter are 

 all of the same length, very long and much constricted at the 

 middle. They appear to be entirely cartilaginous in a fresh 

 skeleton, but as they dry a fine hard calcareous matter becomes 

 evident. The hypobranchial of the fourth arch is missing, as in 

 all other teleosts (so far as known). The ceratobranchial of the 

 fourth arch is as long as the combined length of the ceratobran- 

 chial and the hypobranchial of the third arch, 1 and opposite the 

 union of these two elements it is angulated, so that its lower 

 part has the appearance of being the fourth hypobranchial. The 

 superior pharyngeals of each side are anchylosed into a single 

 tooth-bearing bone. The inferior pharyngeals are in contact 

 only at their anterior ends. 



A very small nodule of bone between the hypohyals on the 

 lower surface represents the urohyal, and another on the upper 

 surface the glossohyal. Only one of the hypohyal elements is 

 present on each side. The suture between the hypohyal and the 

 ceratohyal runs vertically upward from the lower side of the arch 

 half way across the arch, then turns squarely and runs horizon- 

 tally backward for nearly half the length of the ceratohyal, where 



1 I am not aware of any similar arrangement in any other Teleost. The hypo- 

 brachials usually decrease in length so rapidly posteriorly that their absence on the 

 fourth arch does not require a lengthening of the fourth ceratobranchial ; all of the 

 ceratobranchials being of about the same length. 



