. Bulletin of the Museum of Comparative Zoology at Harvard College. Zoology. WALTERS : BIOLOGY OF THE GIGANTURIDAE 305 The walls of the medulla oblongata are thickened but there are no enlarged sensory lobes. The stoutest cranial nerves are the auditory (VIII), facial (VII), trigeminal (V), and optic (II) ; the olfactory (I), oculomotor (III), trochlear (IV), and abdu- cens (VI) are thread-like; the glossopharyngeal (IX) and vagus (X) are intermediate in stoutness. The pineal body is large and applied to the inner surface of the frontals near the supra- occipital; B. lisae has a foramen above
. Bulletin of the Museum of Comparative Zoology at Harvard College. Zoology. WALTERS : BIOLOGY OF THE GIGANTURIDAE 305 The walls of the medulla oblongata are thickened but there are no enlarged sensory lobes. The stoutest cranial nerves are the auditory (VIII), facial (VII), trigeminal (V), and optic (II) ; the olfactory (I), oculomotor (III), trochlear (IV), and abdu- cens (VI) are thread-like; the glossopharyngeal (IX) and vagus (X) are intermediate in stoutness. The pineal body is large and applied to the inner surface of the frontals near the supra- occipital; B. lisae has a foramen above the pineal, but in G. vorax the frontals are separated by a cartilaginous wedge over the pineal. The pineal stalk is remarkably long and robust; at the rear of the stalk is a pair of macroscopic habenular bodies (microscopic in most teleosts). The hypophysis has a remark- ably long and slender stalk. The labyrinth of Gigantura chum was studied by Bierbaum (1914) ; the sacculus is smaller than the utriculus. In a speci- men in the American Museum of Natural History (No. 20393) the plane of the horizontal semicircular canal parallels the longi- tudinal axis of the head and body. The eye of B. indicus was described in detail by Brauer (1908) ; my material of B. lisae and G. vorax has not been studied in this regard. The olfactory capsule is almost microscopic and the slender olfactory nerve passes through the orbit dorsal and medial to the oblique muscles (in both genera). The lateral line system is fairly well de- veloped on the head although difficult to trace in entirety owing to loss of skin; the infraorbital canal is particularly well de- veloped in Gigantura, and is contained in flexible lightly-ossified P,1. K1ZET Figme 7. Brain and cranial nerves of Gigantura vorax, American Mu- seum of Natural History 20393. Abbreviations: I, olfactory n.; II, optic n.; III, oculomotor n.; IV, trochlear n.; V, trigeminal n.; VI, abducens n.; VII, facial n.: VIII, auditory n.; IX, glossoph
Size: 2219px × 1126px
Photo credit: © Book Worm / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookauthorharvarduniversity, bookcentury1900, booksubjectzoology
