46 PEOF. W. K. PAEKER OX THE 



and intelligence : a Rook has a lesser body than an average Tinamou, but it has three 

 times its bulk of brain ; the Raven and the Ostrich stand at the extremities of the bird 

 series. Opisthocomus is not the only Neotropical type that belongs to the region round 

 about the Ostrich territory ; I have just mentioned the Tinamous, and there are several 

 other rare, unclassifiable, and manifestly archaic types in the rich Avifauna of the 

 American Tropics. It is in the Neotropical Region that we find the most archaic forms 

 of every family. It is there also that we meet ^vith the low harsh-voiced Passerines, 

 aberrant in various ways ; Cuculine forms that are so torpid that they become a mass 

 of fat [Steatornis) ; and true Cuckoos {Geococcyx, &c.) that walk the ground firm, like 

 Fowls, and have a pelvis that is strongly Ornithoscelidan. In this region, also, there 

 are birds related to Geese that have the face of a Hen (Palamedeidae) ; and a genus 

 of the Crane family {Psojihia) with a Pea-fowl's head and the bony brows of a 

 Tinamou. These and various others characterize the rich and unique Avifauna of this 

 region. Nor are these all the rare and isolated types to be found there ; we have, 

 also, Eurypyga, Bicholophus, Attagis, Thinocorus, Chionis, Pha'ethon, and Tachypetes. Of 

 course the Eastern Region south of " Wallace's Line " yields many important and rare 

 forms, especially among the Ratitse; but for archaic Carinatae it is far inferior to 

 the Western Tropics. 



The type now under consideration, being the only one of its family, and considered 

 by Prof. Huxley to represent, not a Family merely, but a Suborder or a bundle of 

 Families (the Heteromorphse), must of necessity be archaic, for all its near relations 

 have been weeded out in the past. This is as self-evident on one hand, as, on the other, 

 it is a sure induction that the wise Raven is a modern type ; for he has not only 

 acquired all the highest accomplishments of which a bird is capable, but, as the head 

 of a long list of Families, he has an ornithological following of more than six thousand 

 species, or half the number of existing birds. 



Anticipating somewhat the descriptions now to follow, I may remark that, besides its 

 isolation as a type, 0])isthocomus\s aberrant as a Carinate bird in the Struthious character 

 of its palate ; its temporary basipterygoids are Tinamine ; its scapula is Batrachian ; its 

 three clavicles are more Lacertian than those of any other bird ; whilst its sternal keel 

 is permanently rudimentary. Its wing also has the largest claws in it of any known 

 kind, with a rudiment of a third claw and two rudiments of a fourth digit ; and to 

 crown all, for a time, it has, before hatching, eight distinct carpals ; and the inter- 

 medium of the tarsus is one of the longest and best developed ever yet seen by me in 

 any bird. Of course, the existence in these days of a bird like this is not merely a 

 " foreign wonder " to the ornithologist ; its great importance lies in the light it sheds 

 on the uprise of the feathered types during time. A comparison of the ankle-joint 

 of the bird, in its early state, with what is extinct in the Ornithoscelidan Reptiles was 

 a great stroke in this enquiry ; but it is only in the hips and hind limbs that those 

 Reptiles resemble immature birds. In the length of the neck, and in the shortness of 



