510 MR. W. K. PARKER ON THE OSTEOLOGY OF THE KAGU. 



rowest part, and is much dilated at its base, which turns inwards and forwards. There 

 are a deep " quadrato-jugal cup," a high and neatly finished semioval convex " pter}'goid 

 condyle," and two reniform convexo-concave condyles for the " articulare;" the inner of 

 these is the lesser, and has the " hilum " looking backwards ; the outer has its concave 

 margin looking forwards and inwards. 



The mandibles are typically Gruine, but there is a good Ardeine character even in 

 them ; this is the long retral process between the mandibles (PI. XCII. fig. la), growing 

 backwards from the ankylosed symphysis'. Here, again, the Kagu and the Eurypyga 

 correspond, whilst in the Psophia there is the merest rudiment of this part. The fore 

 part of the dentaries is like the fore part of the intermaxillaries ; further backwards 

 (PI. XCII. fig. 3 a) the ramus is high, as in Anthropo'ides, and only lowers a little in 

 front of the hinge, where it becomes thick also. The fore part of the " coronoid " and 

 the hinder part of the " splenial " is unankylosed ; the " dentary," also, has not coa- 

 lesced with the combined " angular " and " surangular." The fenestra which appears in 

 the Psophia, between the forks of the dentaiy behind, is filled up ; so is that which is 

 seen in the Stanley Crane and the Eurypyga above the root of the " coronoid " and 

 through the substance of the " surangular ; " in this the Kagu agrees with the Grey 

 Heron : there is a trace of this fenestra in Nycticorax. The convexo-concave condyles 

 (PL XCII. fig. 1 a) conform exactly to those of the os quadratum, the concavities and 

 convexities being reversed. The posterior face of the mandible is essentially Gruine, but 

 most evidently Ardeine also ; it is triangular, the upper and outer edge forming a right 

 angle (PI. XCII. fig. 4«). 



The " internal angular process " is blunt, and perforated for the passage of air ; the 

 " outer angular process " is rather sharp, and projects downwards as much as backwards. 

 In the posterior face of the mandible the Kagu agrees with the typical Gruinae, but 

 makes some approach to the Ardeinse ; in the Eurypiyga the Ardeine characters prepon- 

 derate, whilst the same part in the Psophia is about equal to that of the Kagu. 



The ceratohyals are lost in my specimen; I suppose that they were long, slender, 

 and unossified. The basihyal (figs. 8 & 8 ft) is rather long, slender, and well ossified ; 

 the urohyal is small, slender, and scarcely ossified at all ; aud the thyrohyals are slender 

 and feebly ossified. 



The sclerotal ring is ossified ; but the bony plates are scai'cely larger than in Psophia, 

 with a much smaller eyeball. In Bicholophus, which has the eyeball but little larger 

 than that of the Kagu, the sclerotals are twice as large and twice as strong, and the 

 diameter of the ring is but little short of an inch (11| lines) from edge to edge. In the 

 Kagu this diameter is 2 lines less ; and in it the sclerotals turn forwards very little at 

 their inner edge ; in Bicholophus this Owl-character is very strongly developed. 



The vertebrae vary as to number in the Kagu and its relatives, as follows : — 



' In this character the Herons and Pelecanine birds agree ; in the Cormorant and Gannet this process is 

 well developed. 



