115 



ARDEA MAURITIANA (NEWT. & GAD.) 



Butorides mauritianus Newton & Gadow, Trans. Zool. Soc. vol. XIII, p. 289 (1893). 



THE bones on which this species is founded are a pair of ulnae, one radius, 

 four metatarsi, and one coracoid. The description is as follows : — "The 

 bones in question are all considerably shorter than the corresponding 

 bones of A. (Nycticorax) megacephala. The metatarsi agree otherwise in every 

 detail with those of the latter species ; this relative stoutness indicates that 

 they belonged to a Night-Heron or Bittern like A. megacephala. The two 

 ulnae cannot, unfortunately, be compared with those of A. megacephala ; their 

 length, 110 mm., compared with the length of the humerus of A. megacephala, 

 119 mm., shows, however, likewise that they were those of a considerably 

 smaller bird. The single left coracoid agrees in all the features of its dorsal 

 or scapular half with A. megacephala, but its ventral or sternal half differs 

 considerably, first by the much more strongly marked ridge of the linea 

 intermuscularis on its ventral surface, secondly by the almost straight instead 

 of inwardly curved margin between the processus lateralis and the lateral 

 distal corner of the sternal articulation, thirdly by a very low but very distinct 

 and sharp ridge, which arises from the median margin of the coracoid, a little 

 above its median articulating corner. This roughness or prominent ridge is 

 entirely absent in A. megacephala and in all other Herons which we have 

 been able to examine, but at least a slight indication of it occurs in an 

 individually varying degree in Nycticorax and Botaurus. That this coracoid 

 bone belonged, however, to an Ardeine bird is clearly indicated by its whole 

 configuration, notably by the shape and position of the precoracoid process, 

 the various articulating facets at the dorsal end, and the prominent lip on the 

 visceral or internal surface of the median portion of the sternal articulating 

 facet." 



The following are the measurements : — 



Length of ulna Ill — 112 mm. 



Length of metatarsus .... 81 — 87 „ 

 Length of coracoid 48 „ 



Habitat : Mauritius. 



Although megacephala and mauritiana have been placed in Ardea and 

 Butorides respectively, from the short, stout legs and general build, I am 

 inclined to think that all three of these Herons belong to the genus Nycticorax. 



