OCR Text |
Show 1904.] OSTEOLOGY OF THE ELOPID.E AND ALBULIDiE. 47 whereas in Elops it slopes downward and backward. Minute teeth occur on the palatal surfaces of the palatine, entopterygoid, and ectopterygoid bones. Hay (Zool. Bull. ii. 1, 1898, p. 39) states that in Tarpon atlanticvs teeth may occur even on the quadrate. Opercular Series (text-figs. 13 & 14, p. 4(5).-The subopercular is relatively longer and narrower than that of Elops. The branchi-ostegal rays are from 23 to 25 in number. The first thirteen are attached to the lower edge of the ceratohyal, the remainder to the outer face of the epihyal. As in Elops, the series extends along the whole length of the edge of the ceratohyal. The last six branchi-ostegal rays become gradually broader, and the last of all extends farther forward over the outer face of the epihyal than those that precede it. There is a median jugular plate (text-fig. 14, j , p. 4(5) attached by ligament to the back of the mandibular symphysis. Hyobranchial Series. The hyobranchial skeleton bears a close resemblance to that of Elops. The interhyal is ossified. The epihyal is proportionately smaller and the two hypohyals relatively larger than in Elops, and the endosteal glossohyal is relatively greater. The dentigerous patch on the fifth ceratobranchial is readily removable, as in Elops. There is a first pharyngobranchial as well as the spicular bone. It stands more upright than that of Elops. and is attached to the antero-ventral part of the pro-otic. A L B UL1 D iE. A l b u l a CONORHYNCHUS. Sliufeldt (U.S. Fish. Com. Rep. 1883 (1885), pp. 808-813 and figs. 28-31) has described the cranium and hyopalatine arch of Albula. but the other bones of the skull were apparently missing from his specimen. The following remarks are based upon the examination of two skulls. Cranium (text-fig. 15, A, B, & C, p. 48).-The cranium is rather long, straight, and thin. The parietals are small; they are in contact in the median line, and lie over the supraoccipital in such a way that hardly more than the spine of the latter is visible in a dorsal view. The supraoccipital, however, extends well forward, even beneath the frontals, and it is therefore incorrect to state, as Boulenger does (Ann. & Mag. Nat. Hist. (7) xiii. 1904. p. 164), that the supraoccipital is separated from the frontals by the parietals. The posterior temporal fossa is roofed over by the frontal, squamosal, parietal, and epiotic; its floor is formed by the squamosal and pro-otic, its outer wall by the squamosal, and its inner wall bv the pro-otic, supraoccipital, and epiotic. The back of the cranium, immediately on the two sides of the supraoccipital crest, is so hollowed that the term vacuity might almost be applied to these depressions. At the bottom of each depression, surrounded by the supraoccipital, epiotic, and ex occipital, a small piece of the squamosal is visible (text-fig. 15, B, sq.). The subtemporal fossa,, lying just below the posterior part of th e articular surface for the head of the hyomandibular, is bounded entirely by the squamosal and exoccipital in the smaller specimen |