890 THE MIOCENE FAUNA. 



tudinal convolutions in the raccoons; in the civets and cats the inferior 

 convohition is fissured at the extremities, while in the dogs it is entirely 

 divided, so that there are four longitudinal convolutions between the sylvian 

 and median fissures. 



An important set of characters hitherto overlooked confirms Flower's 

 order. I refer to those derived from the turbinal bones. In the ursine and 

 canine forms generally the maxilloturbinal is largely developed, and ex- 

 cludes the two ethmoturbinals from the anterior nareal ojDening. In the 

 Feline group, as arranged by Turner, the inferior ethmoturbinal is devel- 

 oped at the expense of the maxilloturbinal, and occupies a part of the 

 anterior nareal opening. These modifications are not, so far as my expe- 

 rience has gone, subject to the exceptions seen in the development of the 

 otic septa and molar teeth, while they coincide with their indications. The 

 seals possess the character of the inferior group, or Ursidas, in a high degree. 



The characters derived from the paroccipital process are of limited 

 application, as the study of the extinct forms shows. 



In view of these facts, I have proposed the following arrangement:^ 



Mr. Wortman has suggested that the Arctoidea should be distinguished 

 as a primary division, since it diff'ers from the Cynoidea in the articulation of 

 the astragalus with the cuboid bone. I do not, however, find this character 

 to be constant in the Arctoid series. It gradually disappears in the Mus- 

 telidse, and is wanting in 3fustela pennaniii and Procyon nasiia. 



External nostril occupied by the complex maxilloturbinal bone; ethmoturbinals con- 

 fined to the posterior part of the nasal fossa; the inferior ethmoturbinal of reduced 

 size Hypomycteri. 



External nostril occupied by the inferior ethmoturbinal and the reduced maxillo- 

 turbinal Epimycteri. 



While no doubt transitional forms will be discovered, the types at 

 present known fall very distinctly into one or the other of these divisions. 

 The characters are readily perceived on looking into the nares of well- 

 cleaned specimens. The Hypomycteri stand next to the Pinnipedia, since 

 the maxilloturbinal bone has the same anterior development in that group. 



In searching for definitions of the families, it is necessary to be precise 



'Proceedings Ajnerican Philosophical Society, 1882, p. 471, where a list of the genera is given. 



