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Show 1904.] OSTEOLOGY OF THE ELOPIIXE AND ALB( LIDyE. 37 temporal bone is properly regarded as a constituent of the shouldei -girdle; but since Gill and others have laid some stress on the manner in which this bone is attached to the back of the cranium, it is expedient in the present connection to treat it as a bone of the skull. The explanation of the exclusion of the preopercular and interopercular bones from the opercular series is given 011 p. 68. (3) Circumorbital Series.-The lachrymal bone is included in this series of bones set around the eye, but it is considered advisable to avoid the use of this name. The bone differs in no important respect from the others of the .series, and it is not easy to identify if there are several sensory-canal bones present at the side of the snout. The nasal, although shut out from the orbital margin, belongs to the same category, and is included under the present head, unless it be rigidly united with the cranium as above mentioned. The term 11 preorbital " is employed to designate that bone which forms the anterior margin of the orbit. The word is thus not used in the same sense as it is by Allis (Journ. Morph, xiv. 1898), who, in the case of Amia, lias applied it to the lateral ethmoid (endosteal prefrontal). (4) Maxillary Series.-Maxillary, premaxillary, surmaxillary bones. (5) Mandibular Series. -Dentary, articular, angular. (6) Hyopalatine Series.- Hyomandibular, symplectic, quadrate, metapterygoid, entopterygoid, ectopterygoid, palatine. (7) Opercular Series.-Opercular, subopercular, branchiostegal rays, jugular plate. (8) Hyobranchial Series.-All the bones of the hyoidean and branchial arches except the hyomandibular and symplectic bones. E l o p i d .« . E lops sa u r u s . The only published figure of the skull of Elops appears to be that given by Agassiz in his ‘ Recherches sur les Poissons Fossiles,' Atlas, v. pi. G. fig. 1. The figure shows the superficial bones well, and most of them can be readily identified, in spite of the fact that 110 attempt has been made to label them in any way. The following remarks are based upon the examination of four skulls. Cranium (text-fig. 8, A, B, <fc C, p. 38).-The cranium is moderately long and slender as seen from the side ; in a dorsal view the posterior part is of considerable breadth. The parietals are small, and meet in a mesial suture. They lie over the supraoccipital, which extends well forward beneath the posterior parts of the frontals. The character of the family Elopidae given by Boulenger (‘ Poissons du Bassin du Congo,' 1901, p. 46), " os parietaux separant le susoccipital des frontaux," while applying correctly enough to Megalops, does not apply in the case of Elops. The remark is repeated without modification in the later diagnosis of the family appearing in the Ann. & Mag. Nat. Hist. 1904. xiii. p. 164. The |
