HIRUNDININ.E. 155 



Structure and appearance, and. I must say, I cordially agree with 

 these. Apart from their internal anatomy, there is little to dis- 

 tinguish them, except the smaller bill, the number of tail feathers, 

 and the structure of the foot, and a partial link between the 

 two appear to exist in Dendrochelidon In most large tribes we 

 find some groups separated more or less widely from the typical 

 members, and to remove the Swifts from the Swallows, on account 

 of a differently shaped sternum, and the want of the singing muscles 

 of the larynx, appears to me, as it does to others, forced, unnatural, 

 and artificial. I cannot help here quoting Van Hoeven, in his 

 valuable Hand-book of Zoology, with regard to this question : "I 

 trust it is not to be ascribed solely to custom and to prejudice in 

 favor of a division generally adopted, if I cannot divest myself 

 of this opinion, viz., that Swallows and Swifts should be classed 

 together." Kaup, too, has some strong remarks on this subject. 

 " To separate" says he, " the Ci/pselidcs from the Hirundinidm 

 cannot enter the mind of any one whom scholarship has 

 not deprived of all sense of natural order." Again, " from all these 

 arrangements, it would appear that men, otherwise most capable, if 

 pre-occupied in favour of some particular characteristic type, will in 

 accordance with these, and, in defiance of nature itself, tear 

 asunder the most natural connections, merely to unite forms like 

 the Ct/pselidce and Trochilidce, which in all other respects are 

 dissimilar." 



Sub-fam : Hirundininje — Swallows. 



The bill is short, flat, nearly triangular, compressed at the tips, 

 with a slight emargination, the culmen gently bent at the tip, 

 but not hooked. The gape is large, without any rictal bristles. 

 The wings are long and pointed ; the two first quills generally equal, 

 sometimes the first longest. The primary quills are nine in 

 number, the secondaries moderate, covered at the base only by 

 short coverts. The tail is various, even in some, or only slightly 

 emarginate, deeply forked in others. The tarsus is short, the 

 feet small, the middle toe lengthened, the lateral toes nearly equal, 

 and the claws short, slightly curved, acute, and slender. The tarsus 

 is occasionally feathered, and iu some the toes also ; these lust, 



