OCEANODROMA MONORHIS. 



The specimens of 0. socorroensis in the British Museum and in the Rothschild 

 collection measure : — 



a. 



a 



b. 



? 



c. 



s 





? 



d. 





e.f. 





San Benito Isl. (Mus. Rothschild) 

 do. do. 



Coronado Isl. do. 



do. do. 



San Benito Isl. (Mus. Brit.) 

 do. do. 



Wing. 



Tarsus. 



6.0 



. 0.85 



5.9 



. 0.9 



5.9 



. 0.9 



5.7 



. 0.95 



5.9 



. 0.8 



5.9-5.95 . 



. 0.85 



Middle toe 

 and claw. 



0.9 



0.9 



. . 0.95 



0.9 



0.8 

 ..0.8-0.9 



It will, therefore, be seen that O. socorroensis is a smaller bird than O. melania, the 

 wing not exceeding 6 inches in length, and the tarsus and middle toe not exceeding 

 0.95 inches. According to Mr. Anthony O. melania also differs in its note, having a 

 harsher cry than O. socorroensis. 



It will be noticed that in the synonomy of this species I have identified O. 

 socorroensis with O. monorhis, of Swinhoe. I have compared examples from China with 

 others from San Benito Island, and I fail to find any specific characters for the separation 

 of the two forms. The type of O. monorhis is rather lighter grey on the head and 

 throat than most of the American specimens, but a bird procured by Mr. Rickett in 

 the vicinity of Foochow appears to me to resemble the latter in every respect. The 

 measurements of the series from the coasts of Eastern Asia are as follows : — 



a. (Type) Amoy (Mus. Brit.) 



b. ad. Foochow do. 



c. ad. do. (Mus. Rothschild) 

 d. e. c? Gulf of the Amur do. 



/. S ad. do. do. 



The specific name of monorhis is founded upon the misconception that in the type- 

 specimen there was only one nasal opening, and that the nasal septum was wanting in 

 the Chinese species. A close examination, however, reveals the fact that in Swinhoe' s 

 type-specimen the septum is present, but does not extend so far forward as in the other 

 species of Oceanodroma. The nostrils appear to have been plugged by the taxidermist 

 on skinning the bird, and the septum was thus partially obliterated. Dr. Stejneger 

 also failed to find the single nasal opening in the specimen he examined from Japan 

 (Pr. U. S. Nat. Mus., XVI., p. 622), and Mr. Rothschild's birds from the Bay of the 

 Amur have also normal nostrils. 



The identity of 0. socorroensis with O. monorhis naturally increases the range of the 

 species immensely. 



Count von Berlepsch has very kindly sent me for examination the types of his 

 0. monorhis chapmani which he described from the San Benito Islands. I find them 



Wing. 



Tarsus. 



Middle tr.e 

 and claw. 



.. 5.95 . 



. 0.9 



.. 0.9 



.. 6.25 . 



. 0.9 



. . 1.0 



6.3 



— 



— 



..6.2 . 



. 0.9-0.95 



. . 0.9-0.95 



..6.2 . 



. 0.9 



.. 0.9 



' j-1 j 



33 



