^°'ior^^'] ^"UFi^-i-i''T, Ostenlngy of Orthorhamphux mac^niyoslrifi. 5 



If one will compare fig. 7 of Plate II. of the present article with 

 figs. 14 to 19 inclusive of Plate VI., it will readily be ap})reciated 

 that the lacrymal bones are morphologically very different in all 

 of the skulls of the birds so far noticed. 



Either lacrymal in Orthorhauiphus magnirostris does nut a))pear 

 to fuse or anchylose with any of the bones surrounding it with 

 which it articulates. Mesially, it forms in this species the antero- 

 external periphery of the large, ellipsoidal foramen, at the distal 

 termination of the supraoccipital glandular depression, while its 

 postero-external angle juts out beyond the superior free margin 

 of the orbit. It is convex on its dorsal or superior surface, and 

 correspondingly concave below, where it forms a ])art of the 

 roof of the orbit in front. Its descending process is first directed 

 inwards, then outwards, to terminate in a triangular, expanded 

 free extremity that barely clears the infra-orbital bar. The 

 middle part is slender and directed posteriorly, and it is there we 

 find the pneumatic foramen entering on its anterior aspect 

 (fig. I. Plate II.) Anteriorly, it makes an extensive and close 

 articulation with the nasal bone of the same side. 



A lacrymal bone in Gidicnemiis histriatus essentially agrees in 

 form with that element of the skull as I have just described it 

 for Orthorhamphiis, while in other particulars it is quite different ; 

 for, in the first place, it is stouter ; it fuses with all the bones it 

 comes in contact with, the sutures being practically obliterated ; 

 and, finally, it may or may not form part of the periphery of the 

 small foramen in the concavity for the supra-orbital gland. 



Bdonopterus chilensis possesses lacrymal bones much as we find 

 them in CEdicnemiis histriatus, with the exception that the 

 descending portion of either one of them is far more slender, and 

 may be in contact with the outer margin of the pars plana. More- 

 over, it does not reach down so far toward the zygoma, and 

 midway on its anterior border it develops the fine little spicula 

 of bone, pointing forwards, which is found in the same locality 

 in various other true Plovers. This little spine is well shown in 

 Professor Huxley's figure of the side view of the skull of 

 Charadriiis pliivialis, cited above. (Fig. 7.) 



birds that would repay comparison with the skeleton of the subject of the 

 present paper. (Part IX gives a full account of the skeleton of Chioniis 

 minor.) 



Shufeldt, R. W., " On the Alflnities of Aphriza virgata," Journ. Morph., 

 Boston, Nov., 1888, vol. ii., No. 2, pp. 311-340, Plate XXV. Gives figures 

 of the bones of the skeleton of this bird, which has some affinities witfi the 

 Plovers. 



Huxley. Thos. H.. " On the Classification of Birds, and on the Taxonomic 

 Value of the Modifications of Certain of the Cranial Bones Observable in 

 that Class," P.Z.S.. Lond., 1867, pp. 415-472, Figs. 1-36. Parts of the 

 text and several of the figures refer to Plovers and Gulls, which may be of 

 advantage by way of comparison in the present connection. Professor 

 Huxley evidently had before him a skull of Charadriiis pluvialis, in which 

 the foramen at the anterior end of the supra-occipital glandular depression 

 of the right side was incomplete, its periphery on the outer side being non- 

 continuous ; this having been caused by its encroachment upon the margin 

 of the orbit. The foramen on the left side is entire (figs. 7 and 8). 



