482 EXCURSORES. SNATCIIERS. 



genera or families in their natural position, I think they may 

 be arranged into three groups or orders : the first, that of the 

 Excursores, containing the Shrikes, Rollers, Flycatchers, and 

 Chatterers ; the second, or that of the Volitatores, being com- 

 posed of the Swallows, Swifts, and Goatsuckers ; and the third, 

 or that of the Immersores, including the Bee-eaters as well as 

 the Kingsfishers. 



The birds of which the family of Excursoees is composed, 

 namely the Shrikes, Flycatchers, and Chatterers, of which the 

 older systematic writers formed only three genera, but which 

 latterly, on account of their vast number, and the diversity of 

 form exhibited by them, have been divided into numerous 

 groups, have for the most part a peculiar habit of assuming a 

 station on a twig or other eminence, and of sallying forth from 

 it to seize upon insects that may happen to approach, after 

 which they return to their perch, or assume another station. 

 These excursions of theirs, and the dexterous manner in which 

 they snatch their insect prey, have induced me to name them 

 as above. 



They are generally of small size, averaging perhaps that of a 

 Song Thrush, sometimes very diminutive, and seldom exceed- 

 ing a Jay or a Jackdaw. Their bill is short or of moderate 

 length, broad at the base, compressed at the end, the upper 

 mandible having a small decurved tip, behind which, on either 

 side are a sinus or notch, and a toothlike process, which is fre- 

 quently very prominent. The palate is flat ; both mandibles 

 concave toward the end, with a prominent median line ; the 

 tongue narrow, flat, emarginate and papillate at the base, thin- 

 edged, with the point slit or lacerated. The oesophagus is 

 wide, destitute of crop ; the stomach is elliptical, moderately 

 muscular, having two distinct lateral muscles, its epithelium 

 dense and rugous ; the intestine short, and wide ; the coeca 

 very small. The trachea is cylindrical or somewhat taper- 

 ing ; the inferior larynx with four pairs of muscles, sometimes 

 blended into two pad-like masses. Plate XXII, Figs. 1, 2, 3. 



The body is ovate ; the neck short ; the legs very short and 

 small, or of moderate size ; the tarsus much compressed, cover- 

 ed anteriorly with about seven scutella, of which the upper are 



