58 



Incisors 3^, canines jij)? molars 575 ^^ 36. 



Incisors conical, pointed, curved inwardly, single-rooted; the nature of 

 tte teeth immediately adjoining these is doubtfully expressed in the 

 dental formula, because many writers regard them as canines, while 

 others only as premolars in the uppei-, and incisors in the lower jaw, the 

 former being furnished with two roots and the latter with one ; the 

 posterior molars are greatly constricted on both sides along the whole 

 length of the middle of each tooth between the roots, and appear as if 

 two teeth were united together by a slender bond ; indeed the form 

 when viewed from above resembles rudely a seaman's watch-glass , and 

 each is provided with two large fangs, whose length within the sockets 

 occasionally doubles the exposed portion of the tooth. 



Zeuglodon maceospondtltjs,^ Owen. 



Synonyms — Basilosaurus," Harlan. 



Squalodon Or'ateloufi, Gervais. 

 Delpliinoides Crrateloupi, Pedroni. 



Each enlarged part of the molar teeth has a central pulp cavity and 

 concentric striae of growth ; the cranium is very much elongated and 

 contracted from behind the frontals ; occipital region rises by an abrupt 

 slope, as in cetaceans ; inferior jaw, in shape resembles those of the 

 toothed-whales ; dorsal vertebrae are elongated and cylindrical ; cervical 

 vertebrae short. 



The fossil remains of this singular being was first discovered by Dr. 

 Harlan, in 1835, at Arkansas, Mississipi, and he described them in the 

 Transactions of the American Philosophical Society, under the name of 

 Basilosaurus, as belonging to a gigantic reptile. Four years subse- 

 quently these bones were forwarded to Professor Owen, who, by a 

 microscopic examination of the teeth, pronounced the animal to be an 

 aquatic mammalian, a carnivorous whale, but likewise closely related to 

 the Manatee. Other relics having been found at Alabama in 1845, Dr. 

 Griinther and many other zoologists supported Dr. Harlan's views as to 

 the reptilian character of the reniains, while Burmeister and Miiller 

 retained the mammalian theory. Since this latter date, bones in con- 

 siderable quantities, and more perfect in distinctive qualities, have been 

 exhumed, and these appear to coniirm in a satisfactory manner the 

 research and sagacity of Professor Owen in originally arriving at a 

 correct conclusion from the inspection of materials apparently so slight 

 and defective. 



1 IJ.aKp6s, long, and (nroi/SvXos, dorsal vertebrBe. 

 ^ PacTiAevs, king, and aaipos, a lizard. 



