68 THE VOYAGE OF H.M.S. CHALLENGER. 



plaited rather than lobed, last upper molar with two fangs. Adult males with inflatable 

 narial sac. First and fifth toes of hind foot longer than the rest, nails rudimentary or absent. 



Cystophora cristata (Erxleben). Crested Seal. 1 North Atlantic and Arctic Oceans. 



Plwca cristata, Erxl., Syst. Eeg. Anim. p. 590, 1777. 



Cydophora cristata, Gray, Zool. Voy. "Erebus" and "Terror," p. 4, 1844; and Brit. Mus. 

 Catal., p. 41, 1866. 



Occipital crests strong, two sagittal crests formed apparently of the upper border of 

 the temporal ridges ; slight ridge along line of sagittal suture. Nasals elongated, not 

 attenuated, expanding into a somewhat lobate form at the tip ; outer border of nasal 

 articulating only with frontal and superior maxilla, but the most anterior part of this 

 border is free. Anterior nares capacious, the upper third being the widest part, 

 mesethmoids and maxillo-turbinals reaching the opening. Antorbitals strong, post- 

 orbitals indicated by a tubercle. Hard palate truncated at posterior border reaching 

 close to hamulars and a little in front of the anterior border of the glenoid fossa. 

 Zygomatic of temporal curving upwards to reach the tip of orbital process of malar. 

 A distinct groove between tympanic bulla and mastoid temporal ; slight par-occipital 

 processes. Mandible with a longitudinal, incurved, subcondyloid ridge separated by a 

 notch from the incurved angle of the bone ; lower border of body incurved ; coronoid 

 elongated. 



Macrorhinus. 

 Macrorhine, F. Cuvier, Mem. Mus. Hist. Nat, xi. p. 200, 1824. 



Premaxilla with only a horizontal part, lateral boundaries of anterior nares formed 

 exclusively of superior maxilhe, the outline of the nares concave. Tympanic bulla not 

 much swollen in adult male, but relatively flattened and roughened, its outer part being 

 prolonged into an expanded tympanic plate, which forms the wall of a remarkably 

 elongated external meatus, the aperture of which opens outwards. Depression in 

 superior maxilla below infraorbital foramen not very definite. The orbital orifice of the 

 infraorbital foramen opens below the slope formed by the anterior part of the floor of the 

 orbit, which slope is separated by a considerable interval from the posterior edge of the 

 zygomatic root of the maxilla. Mastoid temporal scarcely distinguishable as a process. 

 Posterior border of vomer articulating with vomerine crest of palate in front of truncated 

 border. Mandible with a distinct subcondyloid process, not incurved or greatly 

 elongated, and separated by distinct notch from angle ; lower border of body everted, and 

 with a wide arch between the two lateral halves ; coronoid not elongated. Adult males 

 with a proboscis. Humerus without a supracondyloid foramen. 



1 A specimen of this Seal was caught at St. Andrews in 1872. R. Walker, Scottish Naturalist, November 1872. 



