378 NOTES ON birds' sterna and skulls. 



The sUrna and (jir dies of these two S2)ccimcns of Urinator lumme* vary 

 somewbat iu size and patteru, but uot suliicieutly to deiiiaiul any de- 

 tailed description, lu one the maihibriimi is fairly well pronounced, 

 -while in the other it may almost be said to be absent. A stumpy little 

 hypocleidium is found on either furcula, and iu one of the specimens 

 this articulates with a well-developed facette found upon the anterior 

 curved margin of the sternal keel. Both sterna have eight facets for 

 the costal ribs upon either lateral border. Air does not gain access 

 through pneumatic foramina to either the sternum nor into the bones 

 composing the shoulder girdle in this diver. 



On the sliiU, shoulder girdle, and sternum of Daptmi capensis. — It will 

 be seen from the list of material that he examined that Forbes has 

 already investigated the skeleton of Daption, although he says very 

 little about the skull of this bird in his admirable paper on the Petrels.t 

 In form and general appearance, however, it very closely resembles this 

 part of skeleton in (Estrelata lessoiii, the skull of which bird he figures 

 iu three positions iu the memoir just alluded to (PI. IV, figs. 1, 2, and 3). 

 Kodger's Fulmar has a very similar shaped skull, and I have nearly 

 the entire skeleton of this bird figured iu the above-mentioned osteolog- 

 ical memoir. 



Daption i^ossesses the characteristically broad vomer found in both 

 (Estrelata and Fulmarus, and in it, too, we find the basipterygoidal 

 processes well developed. Thepostero-external angles of the palatines 

 are always rounded off in all three of these genera, while the anterior 

 extremities of these bones curve outwards as they merge with the pre- 

 maxillary and maxillo-palatine on either side. 



We find the symphysis of the mandible in Daption to be very short, 

 and the side of the ramus of this bone at the junction of its middle and 

 posterior thirds is more than double as deep as it is in any other part 

 of its continuity. Viewed from above it is of a typically V-shaped out- 

 line. 



Forbes in his figure (Col. Sci. Mem., PI. XXIV, fig. 2) of the hinder 

 extremity of the sternum of Daption capensis, draws but one rounded 

 *' notch" in it for either side of the keel, while iu the specimen before 

 me, collected by Dr. Streets, there are on either side of the carina two 

 very complete and rounded notches, as may be seen in my drawing of 

 this bone herewith presented. 



My studies in another connection of the sterna of other birds more 

 or less nearly related to Daption compel me to believe that a still larger 

 series of this bone from individuals of the form now under our consider- 

 ation will eventually show that the xiphoidal extremity of the body of 

 its sternum is doubly uotched on either side of the carina, and that in 

 some way or another Mr. Forbes has presented us with an incorrect 

 drawing of this part of the sternum of Daption, or else his specimen 

 came from an immature or perhaps injured bird. 



t Zool. Chall. Exp., Vol. IV. Pt. XL ix 3. 



