56 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 72 



difference. The method by which the increase has come about in the 

 Odontoceti no doubt holds good for the Mystacoceti as well ; the most 

 primitive forms of probably both groups had serrate teeth in aug- 

 mented numbers. 



* (P. 10.) It has become usual to believe that the precursors of the 

 cetaceans were armored mammals with well-developed osseous dermal 

 plates. Heated support for this idea is brought forward by Kiiken- 

 thal (especially in the section " Ueber Rudimente eines Hautpanzers 

 bei Zahnwalen," in Vergl. -anat. u. entwickelungsgesch. Unters. an 

 Walthieren, part 2, Denkschr. d. med. naturw. Ges. zu Jena, vol. 3, 

 pt. 2, pp. 251-258, pi. 16) and by Abel (especially in the section 

 " L'armure dermique," in Les Dauphins Longirostres du Bolderien, 

 Mem. Mus. Roy. d'Hist. Nat. de Belgique, vol. i, 1901, pp. 17-32, 

 with illustrations). Kiikenthal has investigated recent cetaceans; 

 Abel more particularly the extinct forms. (In Abel is found refer- 

 ence to previous literature on the subject.) Kiikenthal imagines that 

 the Cetacea originated from armored land-mammals with armor sug- 

 gesting that of the Dasypodids, and that as sea dwellers they have 

 lost the armor more or less completely ; Abel thinks, in agreement 

 with Dollo, that the armature did not occur in the terrestrial pre- 

 cursors of the cetaceans, but that it arose in the first whales as part 

 of their adaptation to aqviatic life along the coast, and that afterwards 

 it was lost in the more strictly marine members of the group. 



What we have to build upon is the following : 



Together with the first lot of Zeuglodon bones found in Alabama 

 came a few pieces of limestone containing some plate-like, very 

 irregular bones of various sizes. Accounts of these bones are due 

 especially to Joh. Miiller (Ueber die fossilen Reste der Zeuglodonten 

 von Nordamerica, 1849, P- 34' P^- ^7> %• ?)> Carus (Das Kopfskelet 

 des Zeuglodon hydrarchus ; Nova Acta Acad. Caes. Leop. Carol., 

 vol. 22, pt. 2, 1850, pp. 382-383, pi. 39A, fig. 5), Dames und Jaekel 

 (section Ueber den Hautpanzer der Zeuglodonten, in Dames, Ueber 

 Zeuglodonten aus Aegypten, Palaeontol. Abhandl., herausgeg. v. 

 Dames u. Kayser, vol. 5, pt. 5, 1894, pp. 219-221, with illustration) 

 and Abel (1901, /. c, pp. 24-27). From the beginning the possibility 

 has been thought of that the plates were dermal bones of Zeuglodon. 

 They have, however, most often been regarded as doubtful ; perhaps 

 they were bones from the carapace of a sea turtle like Psephophorus 

 or something of the sort ; usually no one has dared to say anything 

 positive. Abel was the first to consider it as proved that they were 

 dermal bones of Zeuglodon; of one of the specimens in question he 



