180 FOURTH RKPORT — 1834. 



Thus, the osseous fishes he terms Poissons Gnathodontes, from 

 having their teeth implanted in the jaws, in contradistinction to 

 the cartilaginous fishes, which he calls Dermodontes, from the 

 teeth in this group adhering simply to the skin. In like man- 

 ner he calls the Branchiostegi of Gmelin by the name of H4t4- 

 rodermes, or fish in which the structure of the skin is variable 

 in its nature, as opposed to the ordinary fish, which he terms 

 Sqiiamodermes. The subordinate groups are established upon 

 the presence or absence, and on the position (either jugular, 

 thoracic, or abdominal,) of the ventrals, leading in too many 

 instances to unnatural combinations as well as separations. 



Latreille in his Families Naturelles considers the cartilagi- 

 nous and osseous fishes as forming two distinct classes in his 

 great division of SolibrancMci, which he terms Ichthyodera and 

 Pisces respectively. He removes, however, the chondroptery- 

 gious fishes with free gills into the latter class, which is pri- 

 marily divided into the two groups of Anomalia and Normalia. 

 The Anomalia comprise, besides the Sturionii of Cuvier, his 

 two orders Plectognathes and Lophohranches. The Normalia 

 include the remaining orders of that naturalist, arranged how- 

 ever somewhat differently from what they are in the Rigne 

 Animal. In the order Acanthopterygietis, before arriving at 

 the families, he adopts a primary division into the two sections 

 Kystophora and Akystica, characterized respectively by the 

 presence or absence of a swimming bladder. 



Risso, in the 3rd volume of his Hist. Nat. de V Enr. MMd., 

 published in 1826, has given an arrangement of this class ac- 

 cording to his own views. His orders, however, are nearly the 

 same as those of Gmelin. He only substitutes the orders 

 Plectogtiathes and Lophohranches of Cuvier for the Branchio- 

 stegi of the former author. 



Besides the above, I am not acquainted with any systematic 

 arrangements of this class, deserving notice, prior to that of the 

 Hist. Nat. des Po/.wo/«*byMM.Cuvier and Valenciennes. In this 

 work, of which the first volume appeared in 1828, the leading 

 groups remain the same as in the Rhgne Animal. The details 

 of the arrangement are however slightly modified*. And un- 



• One alteration consists in the commencing with the osseous, instead of the 

 cartilaginous fishes. Cuvier observes, however, with reference to this point, that, 

 strictly speaking, these groups form two parallel series, neither being superior 

 or inferior to the other. See Hist. Nat. des Poiss., torn. i. p. 419, and Regne 

 Animal (second edit.), tom. ii. p. 376. — Latreille seems to consider the Fish as 

 forming two series, which, after a time, unite and become one. His arrange- 

 ment of the groups in these parallel lines is, however, different from Cuvier'*. 

 See Fam. Nat. p. 115, note (1). 



