No. 2. — The Chimaeroids (Chmyiopnca Raf., 1815 ; Holocephala-Miill., 1834), especially Bhiiiocldmaera and its Allies. By Samuel G arm ax. There are few of the marine animals that on account of structure and relationships to other forms living ami extinct hive as great interest for zoologists and palaeontologists as the Chimaeroids. Their line of descent extends to Devonian times and away beyond and back to a meeting with that of the Plagiostoraia near the point at whicli the latter separated from the bony fishes. That the line has been well traced fur a long distance through the fossils only makes it the more interesting. Item after item of information relating to the group has been carefidly gathered, dis-cussed, and placed on record, but the advances among the recent have been very slow, and those among the fossils, though in some ways much more extensive, have left much to be desired. The type species of Chi-niaera and Callorhynchus have been known since the establishment of these genera by Linne and Gronow, in 1754. jNIore recently other species have been added to each of them. A most important addition to the knowledge of the group dates from the capture of the types of the genus Harriotta, by the United States Fish Commission, and their description by Messrs. Goode and Bean, in 1894, and a little later another was made by the discovery of a Japanese species, by Professor Mitsukuri, in 1895, which was placed in the same genus, named but not described. The importance of the species from Japan was not recognized for some years, until Dr. Alexander Agassiz, returning from one of his explorations of the Coral Islands, saw and purchased a second specimen from a dealer in Tokyo. Dissection of this specimen supplies the reason for existence of this paper; it brings to liglit a number of interesting details concerning Chimaeroids, and some wliich pertain to other forms than that directly under consideration. The following are among the results and conclu-sions, brought prominently forward at this moment, that appear to be most worthy of attention. The species, Rhinochimaera pacifica, is described and figured with details of skeletal and other anatomy. VOL. XLI. — NO. 2
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