100 Mr. H, Seebohm on the 



ClCONIID^E. ArDEID.^. 



1. The temporal fossfe are ob- 1. The temporal fossae are very 

 scurely detiued. strongly marked. 



2. There is no intei'clavicular pro- i2. The interclavicle projects con- 

 cess wathiu the angle of the fur- spicuoiisly within the angle of the 

 ciilum. fiircuhim. 



3. The episternal process is very o. The epistenial process is very 

 small or absent. conspicuous. 



4. The coracoids do not overlap 4. The coracoids overlap at their 

 at their base. base. 



5. The carotid arches are not 5. The carotid arches are corn- 

 complete on any of the cervical plete on half a dozen of the cervical 

 vertebrae. vertebme. 



G. The cervical vertebrae are 0. The cervical vertebrae are 



comparatively short. very long. 



7. The number of cervical ver- 7. The number of cervical ver- 

 tebrae is 17. tebrce is 10. 



8. The ilium in front of the ace- 8. The ilium in front of tlie ace- 

 tabulum is comparatively bi-oad. tabulum is comparatively narrow. 



Of these eight peculiarities none are characteristic of every 

 species. All that can be said is that every species of Stork 

 agrees with a majority of the characters in the left-hand 

 column, and every species of Heron agrees with a majority 

 of the chai^cters in the right-hand column. The inference 

 to be drawn from these facts is that the dift'erentiation of the 

 two families is a comparatively recent event. In their ostco- 

 logical characters Tantalus, Balmiiceps, ^uAScopusixre Storks, 

 but Cancroma is a Heron. That Balaniceps in tropical 

 Africa, and Cancroma in tropical America, should have inde- 

 pendently developed " boat-bills,^^ is a remarkable but in- 

 structive fact. Not only do these curiously-billed birds belong 

 to diflPerent genera, but to different families. Cancroma is 

 a typical Heron, possessing every one of the eight characters 

 enumerated above, except that in the 6th character it ap- 

 proaches the Storks. On the other hand, BaUeniceps is a 

 Stork, and not a Heron, in seven out of the eight characters. 

 In the 5th character it is a Heron, but this peculiarity (that 

 of the two ventral processes on many of the cervical vertebrae 

 meeting to form a carotid arch) appears to be of very little 

 taxonomic value in the Herodiones. In Ciconia hucocephaJa 



