Miscellaneous. 93 



On Nearctos and iElurina. By Dr. J. E. Gray, F.R.S. &c. 



Dr. Theodore Gill, in the ' Annals and Magazine of Natural 

 History ' for this year, xiii. p. 15, with his usual industry as a com- 

 piler, points out that I overlooked two generic names that have been 

 used by Gervais in his < Hist. Nat. Mammiferes,' ii. 1855. Though 

 this book bears the date 1855, the second volume is not in ..the Mu- 

 seum Library, nor have I seen it in any other scientific or other 

 library in this country ; and being a history of Mammalia intended 

 only for popular use, it is scarcely a place in which a zoologist 

 would look for a new genus. 



Dr. Gill states that M. Gervais has established the genus Tre- 

 marctos on account of a " supracondyloid foramen of the humerus, 

 in which it is said to differ from all other Ursidse ; " but Dr. Gill 

 points out that this foramen is found in other Ursidae, and is doubt- 

 less exceptional and monstrous in them. I would ask, as only one 

 skeleton of Ursus ornatus is known, may it not be an individuality 

 in that specimen ? Certainly it is a novelty in zoology to establish 

 a genus on the existence or non-existence of a foramen in the 

 humerus. My genus Nearctos is established on the peculiarity in 

 the form of the lower jaw, shown to be a characteristic peculiarity 

 by the examination of several skulls, a true zoological character. 



In 1867, I established the genus Viverriceps for Fells Bennettii 

 and several other Asiatic cats, because they have an elongate skull 

 and a complete bony orbit. I referred Felis planiceps to this genus, 

 because it had the same kind of skull — overlooking the peculiarity of 

 its having a compressed double-rooted first false grinder in the upper 

 jaw, which is figured by De Blainville in his ' Osteographie,' and that 

 Professor Gervais had proposed the genus Ailurin (JElurina) for 

 this animal in 1855 ; |and Fitzinger called it Ailurogale in 1869. 



I have examined four skulls of this species and find that the pe- 

 culiarity of the false grinder is a permanent character of the species, 

 and therefore propose, as Dr. Gill has done, to retain both JElwrinq 

 and Viverriceps. 



The front upper grinder of Viverriceps is subcylindrical and one- 

 rooted, and differs in size |in different species. Thus, in Viverriceps 

 Bennettii it is small and conical ; in Viverriceps Ellioti it is very 

 small and rudimentary ; it is similar in V. rubiginosa, but very 

 soon falls out. 



On the Metamorphoses of the Acarina of the Families Sarcoptidoe and 

 Gamasidae. By M. Megnin. 



In July and August of last year I communicated to the Academy 

 two notes on the zoological position and physiological function of the 

 little parasitic Acarina referred to the genera Hypopus, Homopus, 

 and Trichodactylus, which, according to my observations, are merely 

 the heteromorphous nymphs of certain Sarcoptidse — among others, of 

 the Tyroglyphi. 



Since this period I have continued my investigations of the meta- 



