580 Messrs. G. M. Mathews and T. Iredale on some 



differences. If bis forms are no better than bis numbers 

 then they must be poor indeed^ for bis data are too con- 

 fused to be at all intelligible. When a writer gives as 

 his average measurements figures larger than his largest 

 example, and then, to show there is no prejudice, in the 

 next case gives as an average a figure smaller than bis least, 

 nothing can be done. We thought simply a misplacement 

 had taken place, and this is observed to be the case in one 

 instance, but altogether it is impossible to determine the 

 truth. Consequently no reliance can be placed upon any 

 measurements given in this paper, and until confirmation by 

 some one able to exactly record measurements accurately 

 taken, and see that they are j^rinted correctly, Emerson's forms 

 must remain obscure to the worker unable to examine topo- 

 types. Emerson has in the same place brought into this 

 confusion Anthony's 0. kaedinqi, so that we have left it alone. 

 We do not mean to disparage Anthony's species, but we fear 

 to add to the confusion. 



O. socorroensis Townsend we should class as a subspecies 

 of Swinhoe's monorhis. It is difficult to separate them, aud 

 they were lumped in the ' Monograph.' 



In that work C. homochroa Coues is called the Ashy Petrel 

 and this vernacular name is used in the A. O. U. Check-List. 

 We are unable to see any reason for this, as the bird is no 

 different in coloration to any other. In the 'Monograph^ 

 it is stated to be lighter than C. monorhis, but we are 

 quite unable to appreciate this distinction. To our eyes 

 the specimens seem darker than the type of C. monorhis 

 Swinhoe. 



The generic character of Oceanudroma of the ' Monograph ' 

 has been above given, and we have already indicated that 

 0. castro does not well agree with the tail character, the 

 fork being almost imperceptible, while the tarsus is certainly 

 distinctly longer than the middle toe and claw. 



In one of the large species, O. meUmia Bonaparte, the feet 



are strong and large and the tarsus is distinctly longer than 



the middle toe and claw, though the tail is long and forked. 



It may be noted that in some of the species of Cyniochorea 



the legs anJ feet arc comparatively strong and in others they 



