[52]. Canu, loc. cit. p. 66.
[53]. The Cambridge Museum possesses two specimens of Philichthys xiphiae, from the frontal bones of a Swordfish (Xiphias gladius) taken off Lowestoft in 1892.
[54]. Claus, Arb. Zool. Inst. Wien, vii., 1888, p. 281.
[55]. Proc. Biol. Soc. Liverpool, i., 1887.
[56]. Zeitschr. wiss. Zool. xlix., 1890, p. 71.
[57]. The genus Pennella also includes parasites on the whales Hyperoodon and Balaenoptera.
[58]. Claus, Schriften d. Gesellsch. Marburg. Suppl. 1868.
[59]. Claus, Zeitschr. wiss. Zool. xi., 1861, p. 287.
[60]. Hansen, “The Choniostomatidae,” Copenhagen.
[61]. Claus, Zeitschr. wiss. Zool. xxv., 1875, p. 217.