150 Zoological Society : — 



externis cum macula rectricis uncB utrinque extimce apieali 

 albis, his flavicante tinctis ; subtus album, tectricibus sub- 

 alaribus et margins campterii Jlavicanti-albis : rostra superiore 

 nigra, inferiore albo ; pedibus pallide fuscis. 

 Long, tota 3*5, alse 2*1, caudse 1"3, rostri a fronte 6"0, tarsi 6'5. 

 This peculiar Todirostrum is quite unlike any other known mem- 

 ber of the genus in colouring. In structure it is generally typical, 

 but with the bill not quite so broad towards the apex as in some 

 others. 



CyCLORHYNCHUS ^aUINOCTlALIS. 



Clare olivaceus, remigibus alarum nigricantibus Jtavicanti-viridi 



late limbatis ; caudafusca, rectricum marginibus dorso con- 



coloribus : subtus Jlavicans, gida grisescente ; pectore et late- 



ribus cum crisso oUvaceo perfusis ; tectricibus subalaribus sul- 



phureis ; rostra sujieriore nigro, inferiore albo; pedibus carneis. 



Long, tota 6*0, alae 2*6, eaudse 2*3, rostri a rictu 0*8, tarsi 0*7. 



This bird is a close ally of the Brazilian Cyclorhynchus olivaceus, 



but may be distinguished by its shorter wings and tail, and by the 



])ure yellow of the middle of the abdomen. 



March 9, 1858.— Dr. Gray, F.R.S., V.P., in the Chair. 



A Monograph of the genus Miniopteris. 

 By Robert F. Tomes. 



Perhaps there is no order of Mammalia in which there is so great 

 a diversity in the forms of the different species as in the Cheiroptera. 

 On examining the genus Fespertilio in the extended form in which 

 it is given by M. Temminck, and more recently by M. Wagner, the 

 naturalist v^'ill find an assemblage of creatures which he will have 

 great difficulty in making out to his satisfaction. But in endeavour- 

 ing to separate them into groups or genera for the purpose of de- 

 scription, he will be equally puzzled. An examination of the British 

 species merely, will illustrate the nature of the difficulty to which I 

 refer. Take, in the first place, the common Noctule Bat, and the 

 equally common Whiskered Bat, the one exhibiting a heavy mus- 

 cular body, and strong wings ca})able of vigorous and sustained 

 flight, and with jaws and teeth of sufficient size and power to masti- 

 cate a Cockchafer whilst on the wing with perfect ease ; and the 

 other species having a slight and feeble body, with very slender 

 wing-bones supporting a membrane of equal delicacy, suited only for 

 flight in sheltered spots, and with a muzzle and teeth of such small 

 size as to be fitted only for taking minute food in such situations. 



The difference between the two is quite sufficient to justify generic 

 separation, and the work is easy so far as these two species are con- 

 cerned ; but unfortunately a whole host of species come in between 

 them, and bring such a series of small modifications as to reduce 

 the distinction to one of degree only ; so that in attempting to separate 



