190 • Annals of the Carnegie Museum. 



as a separate piece in some forms, notably tlie Passerine birds, and 

 may be compared with the pro-coracoid of reptiles. Not having a 

 young, or rather a sufficiently young enough Heron, at hand, I am 

 unable to investigate the pectoral arch with the view of ascertaining 

 how the development proceeds in the case of the forms under con- 

 sideration. 



Professor Owen, in calling attention to the relation between the hypo- 

 cleidium of the clavicles and the carinal angle of the sternum, in other 

 birds says : " The ])rocess itself reaches the sternum and is anchylosed 

 therewith in the Pelicans, Cormorants, Grebes, Petrels, Frigate- 

 bird, and Tropic-bird, also in the Gigantic Crane, and the Storks 

 in general." I am compelled to take this statement with a little 

 caution — as it does not always anchylose in the Cormorants, fails to 

 do so in a number of the Podicipididce, as in Clark's Grebe ; and, so 

 far as I am aware, rarely in the ProcellariidiV ; I have one or two e.x.- 

 ceptions before me ; the least tendency to form such a union being seen 

 in the Grey Fork-Tailed Petrel, (^Oceanodroiiia fiircata) . 



In all of these forms, however, the hypocleidium is in more or less 

 intimate relation with the anterior border of the keel of the sternum. 

 I have examples where the closeness of the contact is very intimate 

 and requires special investigation to determine whether true anchylosis 

 really exists or not. This is so even in Oceanodronia and Colymbus 

 sometimes. I have several skeletons of the former before me, but I 

 have figured one where it was the least so. No doubt these facts ac- 

 companied by the lack of good material led Professor Owen to make 

 the above statement. It holds good for our United States Gruidce, as 

 Griis canadensis, and G. ainericanus, but not for Arainus. 



Of t/ie Fch>is and Coccygeal Vertebm. — Many years ago I made 

 a number of anatomical drawings for Professor Coues, these now 

 illustrate his admirable "Key to North American Birds," 2nd Edi- 

 tion. Among these drawings I figured the under view of the pel- 

 vis of A. hcrodias, the bone now to be described. It is figure 60, 

 in the work cited and as the present memoir contains two other 

 views of this pelvis (Figs. 13 and 14) I have intentionally drawn 

 them from the same specimen, which I was so fortunate as to still 

 have by me. 



The twenty-fourth vertebra of the spinal column of this heron is 

 the anterior one of the series that becomes incorporated by complete 

 anchylosis with those neighboring bones which go to form the pel- 



