210 Annals of the Carnegie Museum. 



be remembered that I only present the length of the chord from the 

 tubercle on the inner side of the proximal extremity to the apex of the 

 joint. 



Herons possess no special ossifications other than those I have men- 

 tioned, that I am aware of, in their skeletons. 



They have, in addition to their general structure, three peculiar ex- 

 ternal characters in common with a no less remotely related group of 

 birds than the Capi-imiil^i. Coues, in characterizing the Night-jars, 

 says : " Besides the semi-palmation of the feet, there is another curious 

 analogy to wading birds ; Ibr the young are downy at birth, as in 

 Fnecoses, instead of naked, as is the rule among Altriccs.'' (Key, 2d 

 Ed., p. 448.) This author does not mention there however, a 

 third character, it no doubt having slijij^ed his mind at the time 

 the above-quoted paragraph was penned. It is, that both the 

 Caprimiilgi and the ArdeiiicE possess in common that very rare 

 character — the true pectination of the inner margin of the claw to 

 the middle toe of pes. This character is also seen in Fregafa, a form 

 far removed, osteologically, from the true Herons. 



Synoptical ami Comparative Review of tiie cliief Osteoioi:;icai Clia fac- 

 te rs of certain species of Nortli American ArdeincB. 



1 . In all the North American Ardeince the superior osseous mandible is 

 of a subpyjamidal form, with its base merging into the skull and its apex 

 at the tip of the beak. It has three sides, the angle of the culmen 

 being rounded off, the other two angles being cultrate. In length it is a 

 little less than twice as long as the remainder of the skull, being 

 notably j-//w/<!V' in some of the Night Herons than in the genus Ardea. 



2. Osseous internasal septum very incomplete or altogether absent. 



3. All are acutely holorhinal birds. 



4. All have (in the dried skull) a moderate movement at the 

 cranio-facial hinge ; best marked in the Night Herons. 



5. Ethmoid much swelled ; broad and spreading under the frontal 

 region ; and truncated transversely in front, just posterior to the line 

 of the cranio-facial hinge. 



6. Pars plana very feebly developed both in Ardea and the Night 

 Herons. It fails to meet the inferior and backward extending process 

 of the lacrymal on the same side. 



7. Very large, spongy maxillo-palatines, lofty and parallel to each 

 other in the rhinal chamber, attached to nasals and premaxillary by 



