20 Mr. F. E. Beddard on the 



it is prefaced with some general considerations, in which the 

 antlior brings forward a great nnmber of facts relating to the 

 presence or absence of the structnre known as the after- 

 shaft in the bird's feather, and in many cases contradicts 

 the statements made by Nitzsch in his classical work npon 

 Pterylography *. 



Thus, with respect to the Swifts, in Avhich birds the feathers 

 are stated by Nitzsch to be furnished Avith an aftershaft. 

 Dr. Uochebrune remarks : — " MalgTe nos recherches les 

 plus minutieuses, aucune espece des genres Cijpseliis, Chatura 

 kc, ne nous a fourni de plume adventice, et nous affirmons 

 que toutes indistinctement en sont depourvues." 



I have examined one species of each of these genera, viz. 

 Chatura zonaris and Cypselus apus, and find that a distinct 

 aftershaft is present in both of them. The accompanying 



Pectoral feather of Chatura zonaris, from behind, 

 to .show the aftershaft. 



woodcut is a copy of one of the pectoral feathers of the 

 former species ; the aftershaft is here large and well deve- 

 loped, attaining to rather more than half the length of the 

 feather itself. 



In Cypselus apus the aftershaft is entirely similar. 



In other cases it is rather difficult to follow Dr. Roche- 

 brune's criticisms, and the discrepancies between his state- 

 ments and those of Nitzsch seem often to be due to a 

 different conception of what an aftershaft is. Nitzsch defines 

 it as follows {op. cit. p. 89) : — " The aftershaft originates from 

 the underside of the feather beneath the umbiliciform pit ; it 

 resembles the main shaft, and, like it, emits two series of 

 barbs, thus forming alopg with the shaft an apparently 



* ' Pterylography,' English edition (Loudon, 1867). 



