BIRD RECORDS FROM CALVERT FORMATION WETMORE 25 



interest when tliey become available. To signalize this character in 

 Sula avita I propose to erect for it Microsula as a new subgenus, with 

 Sula {Microsula) avita as its type. 



MORIS species 



On July 10, 1937, Mr. Collins secured the proximal end of a right 

 ulna of a bird of this group at a point 1 mile south of Plumpoinfc 

 wharf. The bone (U.S.N.M. no. 15475) was obtained from zone 10, 

 about 2 feet above the heavy shell layer. Though there is some indi- 

 vidual variation in the modern species of gannets, the genus Moris 

 differs from the boobies, genus Sida^ in having the internal cotyla 

 of the ulna more elongated in form. This does not always hold but 

 is true in a number of specimens that I have seen. The Plumpoint 

 specimen is referred to Moris on this basis. 



The fragment seems to come from a bird slightly larger than living 

 Sula leucogaster. It appears to be from a smaller individual than 

 the bones that are known from Moris loxostyla (Cope) but may be 

 that species, which comes from the Miocene of Maryland and New 

 Jersey. It is identified, however, only to genus. 



Family COLUMBIDAE 



A distal portion of a left radius (U.S.N.M. no. 15159) collected 

 by R. Lee Collins, September 8, 1936, 1.6 miles south of Plumpoint, 

 Md., in zone 10 of the Calvert formation, represents a species of the 

 pigeon family. It comes from a bird slightly larger than the living 

 mourning dove {Zenaidura maxiroura) . 



Though it is an interesting record of a member of this group, it 

 cannot be identified except to family because of its fragmentary 

 nature and the lack of specific characters in the radius of birds in 

 general. It is the oldest record in North America for this group 

 of birds. 



U S GOVERNMENT PRINTIN6 OFPICEl l»S7 



