36 DR. AV. G. RIDEWOOD OX TJIE CRANIAL [May 3, 



KSiiggestioiis and advice from Dr. A. Smith Woodward, Mr. G. A. 

 Boulengei", and Mr. C. Tate Regan at the British Museum 

 (Natural History). 



The mode of disarticulation and preparation of the skull adopted 

 for the purpose of the present inquiry may be recommended for 

 general use. It is obvious that, the skulls of Teleostean fishes, 

 prepared as one now finds them in museums without the disarticu- 

 lation of any of the parts, are unsatisfactory, by i-eason of the 

 impossibility of studying miniitely any but the most superficial 

 bones. On the othei- hand, the maceration of the skulls until all 

 the bones fall apa,rt is equally open to objection, since, if the bones 

 are stored loosely in a box, a great deal of time is wasted in 

 sorting out the parts for study ; while if the bones are wired at a 

 little distance from one another in the manner introduced by 

 Owen, the mounted skull is unnecessarily bulky, and there is 

 always the possibility of eri'or in the process of rearticulation ; and 

 the expense is so gi'eat as to prevent the general adoption of the 

 method. If, however, the skull be disai-ticulated into four parts 

 as described below, the whole of the bones of the skull can be 

 studied closely, the skull when stored occupies no more room than 

 if no disarticulation had been made ; the several parts can be 

 rapidly placed in position for studying their mutual relations, 

 and thei'e is no possibility of erroneous rearticulation. 



From the fresh head, or one preserved in spirit, the nasal *, 

 lachrymal, circumorbital, premaxillary, and maxillary bones of 

 the left side are removed in one piece, and are carefidly cleaned in 

 such a way as to prevent their coming apart. The left palatine 

 and left hyomandibular are then disarticulated from the cranium, 

 the mandibular symphysis is severed, the left interhyal bone is 

 <iisarticulated from the hyomandibular, and the whole hyoman- 

 dibular- palatine arch of the left side, together with the left ramus 

 of the mandible and the opercular bones of the left side, are 

 removed in one piece, and are prepai^ed without further dissocia- 

 tion. The whole hyobranchial skeleton (with the exception of the 

 hyomandibular and symplectic bones) is then removed and pre- 

 pared in one piece. The remainder of the skull is prepared in 

 one piece : it exhibits all the bones of the right side in theii- 

 undisturbed relations, and at the same time presents a freely 

 exposed left view of the cranium. 



It has been found convenient to consider the constituent parts 

 of the skull grouped as follows : — 



(1) Craniimi. — The term Cranium, as applied here, is a con- 

 venient appellation for that complex of not readily separable bones 

 disposed around the brain. It includes the vomer and para- 

 sphenoid, belonging strictly to the buccal series, and in some cases 

 (e. g. Osteoglossum) the nasal bones. 



(2) Temporal and Preopercular Series. — Post-temporal, supra- 

 temporal, subtemporal, preopercular, interopercular. The post- 



* In such skulls as those of the Osteoglossidse the nasal is not removed with this 

 series, but is left with the cranium. 



