xii THE ORDER PRIMATES 159 



which the generic term GaleopitJiecus has since been applied. 

 It is one of those completely aberrant forms which, having no 

 near existing relations, and none yet discovered among extinct 

 forms, are perfect puzzles to systematic zoologists. It is 

 certainly not a lemur, and not a bat, as has been supposed by 

 some. We shrink from multiplying the orders for the sake of 

 single genera containing only two closely-allied species ; so we 

 have generally allowed it to take refuge among the Insectivora, 

 though without being able to show to which of that somewhat 

 heterogeneous group it has any near affinities. 



The fourth genus of the PRIMATES is Vespertilio, comprising 

 six species of bats. This genus has now by universal consent 

 expanded into an order, and one of the best characterised and 

 distinctly circumscribed of any in the class : indeed, those 

 who have worked most at the details of the structure of bats 

 find so much diversity in the characters of the skull, teeth, 

 digestive organs, etc., associated with the modification of the 

 fore-limbs for flight common to all, as almost to entitle them 

 to be regarded rather as a sub-class. Anatomical as well as 

 palteontological evidence shows that they must have diverged 

 from the ordinary mammalian type at a very far distant date, 

 as the earliest known forms, from the Eocene strata, are 

 quite as specialised as any now existing, and no trace has 

 hitherto been discovered of forms linking them to any of the 

 non-volant orders. By the publication within the last few 

 weeks of a valuable monograph on the existing species of the 

 group, entitled " A Catalogue of the Chiroptera in the Collec- 

 tion of the British Museum," by G. E. Dobson, we are enabled 

 to contrast our present knowledge with that of the time of 

 Linnaeus. Although the author has suppressed a large number 

 of nominal species which formerly encumbered our catalogues, 

 and wisely abstained from the tendency of most monographists 

 to multiply genera, he describes four hundred species, arranged 

 in eighty genera ; nearly double the number of species, and 

 exactly double the number of genera, of the whole class 

 MAMMALIA in the Systema Naturce, and these Dr. Glinther 

 remarks in his Preface are probably only a portion of those 

 existing. The small size, nocturnal habits, and difficulty of 

 capture of these animals, are sufficient reasons for the supposi- 



