272 PROCEEDINGS OF THE ACADEMY OF 



generalized tj^pe, manifested as such by the less specialized denti- 

 tion, as well as by such osteological characters, among others, as 

 the greater development of the representative of the pelvis (made 

 known by Kaup) and the larger and more approximated nasal 

 bones. 



The forms to be approximated to Halitheriiim, as the nearest 

 all}^, iSj in tlie present condition of our knowledge, a problem 

 concerning which a reasonable difference of opinion ma}' prevail, 

 Halicore and Manalus {Trichechus) each having claims to such 

 alliances. Brandt has, however, conjoined with it, as a more 

 immediate relation, the genus Halicore (to which naturally- suc- 

 ceeds Rhyiina)^ and has associated the three genera mentioned 

 in a single famil}', to which he has given the name Halicoridae} 

 The differences between those genera arc, however, of greater 

 taxonomic value than generic, and appear to well merit the 

 distinction of family rank, which has been already conferred 

 on them by several naturalists. "With such value, therefore, 

 those genera iiave been accredited now, but as the}' form a 

 natural series they have been combined in a special superfamily 

 (Hulicoruidea). The difference between the extremes of that 

 superfamily is, at least in some respects, greater than between its 

 most generalized t3pe and the remaining well-known members of 

 the order {Trichechidse or Ilanatidee) and to mark the limit 

 in a specialized direction of the series, the superfamily is adopted. 



The Manatidse {Trichechidse) succeed then, not as most nearly 

 related to the extreme term of the preceding series, but as so 

 nearl}' related to the proximal term as to perhaps even merit 

 further examination, whetlier they are not reall}' more nearl}^ 

 related to it than the dugongs, and consequentlj- better entitled 

 to be associated with it in contradistinction to the others. The 

 capital character of the Halicoridae of Brandt (the Halicoroidea 



Sixit'-me si'ric. Sciences niatheniatiques, physiques et naturelles. Tome 

 VII. Secontle partie : Sciences naturelles. Tome V. . 1849. Zoologie 

 ct physlologia, 1160, pi. 1 5. 



Symbohc sirenologicfc. Fasciculus II. etIII. Sireniorum, Pachj'derma- 

 tum, Zeuglotlontum et Cetaceornm onlinis osteologia comparata, nee non 

 Sireniorum generum monographije. ..... Petropoli, 18G1-C8. [-Ito., 3 p. 1. 



(383 -+- 1) pp. 9 pL] <Ib., VIP serie, Tome XII., No. 1. 



' The outlines of the brain, as illustrated by Brandt, seem to verify the 

 naturalness of this classification. 



