50 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. ^2 



elementen sich immer neue anlegen, indem sie sich, in distaler Richtung 

 aufeinander folgend, in dem sich immer waiter vorschiebenden em- 

 bryonalen Bindegewebe entwickeln, so dass die letzte Phalanx die 

 jiingste ist " (/. c, 1893, p. 311). Kiikenthal finds a reason to reject 

 this Opinion in the fact that Leboucq and he have occasionally found 

 something on the outermost tip of one of the digits of a long-fingered 

 porpoise hand which might be interpreted as the weakest remnant of 

 a nail. Should it prove that remnants of a nail are found on the 

 extreme tip of the finger, says Kiikenthal, this " hypothesis " con- 

 cerning the origin of the many phalanges cannot be correct, " denn 

 dann entspricht die Spitze der Walflosse und damit die Spitze von 

 deren Fingern auch der Spitze der Finger der typischen Vorder- 

 extremitat " (/. c, 1893, p. 312). This objection cannot hold; there 

 is certainly nothing to prevent that the atrophied remnant of a nail 

 should constantly retain its position on the finger tip as this pushes 

 outward further and further, whatever the method by which the 

 finger is elongated. 



^ (P. 5.) A special treatise on the cervical vertebrae of the Cetacea 

 is due to Reche : Ueber Form und Funktion der Halswirbelsaule der 

 Wale; Inaugural-Diss., 1904, with illustrations. See also De Burlet: 

 Beitrag zur Entwickelungsgeschichte der Wirbelsaule der Cetaceen ; 

 Morphol. Jahrb., vol. 50, pt. 3, 1917, pp. 373-402, with illustrations. 



" (P. 7.) On the tympanic bone and its surroundings in the 

 Cetacea, see especially : Van Kampen, De Tympanaalstreek van den 

 Zoogdierschedel, 1904, pp. 299-316. Contains references to earlier 

 papers on the subject. On the ear-bones themselves, see especially: 

 Doran, Morphology of the Mammalian Ossicula Auditus ; Trans. 

 Linn. Soc. London, ser. 2, Zoology, vol. i, 1878, pp. 450-464, 

 pis. 62, 63. 



' (P. 9.) The opinion that the increase in the number of teeth in 

 the Cetacea above the typical eutherian number was perhaps initiated 

 by the intercalation of milk teeth in the permanent set was expressed 

 in 1882 (Vidensk. Medd. for 1882, pp. 31 and 40) at a time when no 

 trace of tooth succession had yet been detected in whales. The same 

 opinion was maintained by Max Weber (Urspr. der Cetaceen, 1886, 

 pp. 195 and 199), but he abandoned it (Die Saugethiere, 1904, p. 567) 

 after Kiikenthal had demonstrated indications of the tooth succession. 

 Kiikenthal had found traces of germs of both forerunners and suc- 

 cessors to the teeth which stand in the Cetacea as the permanent set 

 (but which he considered as milk teeth). Perhaps the idea is wrong ; 

 but there is nothing in that which has thus far been discovered which 



