
ZYGHNOCEPHALUS—ZYGOMATURUS. Fear 
Zygeenocephalus—Continued. 
Apparently a lapsus for Sphyrocephalus in the name on the plate. In the descrip- 
tion (pp. 8-11), the species is given as Sphyrocephalus labrosus, from Old Calabar 
River, West Africa. 
Zygenocephalus: Cvyarva, the hammer-headed shark; Ke~ad7, head—from the 
massive, hammer-shaped head. (See Sphyrocephatlus. ) 
Zygodon Owen, 1839. Cete, Basilosauridee. 
Athen:eum, London, No. 585, pp. 35-86, Jan. 12, 1839; Echo du Monde Savant, 
Paris, 6° ann., No. 405, p. 44, Jan. 19, 1839; Buckiey, Am. Journ. Sci. & Arts, 
XLIV, No. 2, pp. 409-412, Apr., 1843; Edinb. New Philos. Journ., XX XV, 
77, 1843. 
New name for Basilosaurus Harlan, 1824, which was considered inappropriate. 
Zygodon probably antedates Zeuglodon Owen, 1839, although the latter was the 
name finally adopted by Owen, and the one which has been generally accepted. 
Extinct. 
Zygodon: Cuy óv, yoke; 660v=660vs, tooth—in allusion t^. :» posterior molars, 
which resemble two simple teeth tied together. 
Zygodontomys ALLEN, 1897. Glires, Murid:e, Cricetinze. 
Bull. Am. Mus. Nat. Hist., N. Y., IX, 38, pl. 1 figs. 1-7, Mar. 11, 1897. 
Type: Oryzomys cherriei Allen, from Boruca, Costa Rica. 
Zygodontomys: Cuy óv, yoke; dd0vs, tooth; 0s, mouse—from the character of 
the molars. ‘The cross furrows between the successive pairs of cusps are cut 
off by a longitudinal bar of enamel, yoking together the pairs of cusps on the 
median line of the tooth. Thus the anterior coneof M. ! is connected with 
the succeeding pairs of cones by a median longitudinal ridge, and the two pairs 
of cones in M ? are similarly connected. The same structure also characterizes 
the lower molars." (Arrrw.) 
Zygogeomys Merriam, 1895. Glires, Geomyidee. 
N. Am. Fauna, No. 8, pp. 24, 26, 195-198, numerous pls. and figs., Jan. 31, 1895. 
Gygogeomys ALLEN, Science, new ser., !, No. 9, p. 242, Mar. 1, 1895 (misprint). 
Type: Zygogeomys trichopus Merriam, from Nahuatzin, Michoacan, Mexico. 
Zygogeomys: Svp óv, yoke; +Geomys—‘‘in reference to the unique character of 
the zygomata." (MkznmniaAw.) 
Zygolestes AMEGHINO, 1898. Marsupialia, Epanorthid:e. 
Segundo Censo Nac. Repüb. Argentina, 245 footnote, 1898; ibid., Supl., Sinop. 
Geol.-Paleont., July, 1899 (sep. p. 7). 
Type: Zygolestes paranensis Ameghino, from Argentina. 
Extinct. 
Zygolestes: Cvy ov, yoke; An6rns, robber—in allusion to its intermediate position 
between the Garzonid:e and C:enolestid:e. 
Zygolophodon Vacexk, 1877. Ungulata, Proboscidea, Elephantid:e. 
Abhandl. K. K. Geol. Reichsanstalt, Wien, VII, Heft 4, p. 45, July 1, 1877. 
Species, 4: Mastodon borsoni Hays, from the Pliocene of Asti, Italy; M. turicensis 
Gaudry, from the Miocene of southern Russia; M. tapiroides Cuvier, and M. 
wv 

pyrenaicus Lartet, from the Miocene of France. 
Extinct. 
Zygolophodon: Cvy ov, yoke; Aóqos, crest; d6@v=d60vs, tooth—in allusion to 
the continuous ridges of the transverse crests of the molars. 
Zygomaturus MacLzav, 1857. Marsupialia, Diprotodontid:e. 
'' Sydney, Australia, Morning Herald, 1857" (fide Owen, Extinct Mammals of 
Australia, 250, 1877); Krerrr, Mamm. Australia, Introd., p. 3, 1871; Trovxrs- 
sART, Cat. Mamm., new ed., fase. v, 1175, Nov., 1898. 
Type: Zygomaturus trilobus MacLeay, from Australia (fide Trouessart). 
Extinct. ‘‘ Founded on a perfect skull." 
Zygomaturus: Coy ja, CvyOuaros, zygoma; ova, tail, 
