382 NOTES ov birds' sterna and skulls. 



described and figured. Tbey are all very perfect and complete, and 

 show every evidence of having been prepared with great care. I notice 

 at the infero-external angle of the 2)ar>^ plccia and hicrymal of this Gull 

 a small Hake like ossicle, freely articulated and directed backwards. 

 This little bone is found on both sides, but is absent in the two skulls of 

 L. californicus. 



My MSS. not being at hand, I am unable to say whether I found any 

 such character present in the Alaskan specimens I examined and fig- 

 ured or not. 



It does not agree either in position or character with the " ossiculum 

 lacrymo-palatinum" as found among the Albatrosses — the "os crochu" 

 of lieinhardt. 



The sternum of this Gull is highly pneumatic, and possesses six 

 hsemapophysial facets on either costal border. On the otlier hand, the 

 bones composing the pectoral arch are completely non-pneumatic and 

 correspondingly heavy. I have fully described these parts elsewhere. 



Tlie skull, 'sternum, and shoulder girdle of Larus californicus. — One of 

 these skulls is rather larger than the other, though the individual char- 

 acters differ but slightly between them, and nothing like as much as 

 we found to be the case in the two skulls of the Red-throated Divers, 

 described above. Lams californicus has a skeleton almost exactly like 

 L. argentatus, except that it is about one-third smaller. It consequeutly 

 demands no particular description in the present connection. 



The sternum and shoulder girdle of Sula (sp. ?). — The manuscript to 

 which 1 have already referred also contains a full account of the skele 

 ton of Sula bassana, thoroughly illustrated by life-size drawings of the 

 vari(|us bones of the skeleton. The specimen before me, however, does 

 not agree with the corresponding parts of that Ganuet, and 1 am strongly 

 inclined to believe that it comes from some other species of the genus, 

 but neither the literature nor the proper material is at present at my 

 hand to enable me to express a trustworthy opinion in the case. This 

 sternum and girdle have the general i^attern, however, of the bones as 

 we find them in S. bassana, where not only the former bone but all of 

 the elements of the pectoral arch are highly pneumatic. 



I find in the specimen before me five facets for the hi© m apophyses on - 

 either costal border, while the xiphoidal extremitj" shows a deep and 

 rounded notch on either side of the carina, and so fashioned that the 

 lateral processes formed by them are far more prominent than the mid- 

 projection standing between them ; or, in other words, these ^' notches" 

 merge into each other in the middle line, forming as they do so an in- 

 conspicuous mid-process. The sternal keel is lost upon tlie under side 

 of the body of this bone at some distance before it reaches the posterior 

 margin, while anteriorly it projects forward in a very prominent man- 

 ner, where the lower mid-enlargement of tlie furcnla articulates with 

 it, but does not anchylos, as it is said to do in Tachypatcs. Each cora- 



