STEGANOPODES. 179 



curious original of the accompanying wood-cut, the South American boat-bill ((7. 

 cochlearius) is the object of considerable diversity of opinion. To all external 

 appearance, with the exception of the remarkable bill, which is greatly depressed and 

 dilated laterally, the lateral outline much bowed, the boat-bill is a night-heron, that is, 

 its general proportions, size, ornamental feathers, and coloration are those which char- 

 acterize the night-herons. But while it resembles a night-heron, and originally may 

 have.sprung from the same stock, it is modified and specialized in so many ways and 

 so important features, besides the bill and the consequent alteration of the skull, that 

 we necessarily must regard Mr. Robert Ridgway's view as the most justifiable of the 

 two" mentioned above. As specializations additional to the strange conformation of 

 the beak may be mentioned that the boat-bill has lost both the femoro-caudal muscle 

 and the feather tufts on the oil gland, and that it has acquired a fourth pair of 

 powder-down -patches. Grading our groups on a somewhat different principle, how- 

 ever, we include the two species of boat-bills (a new species from Central America 

 having been described this year by the last-named gentleman as Cochlearius zeledoni) 

 in the sub-family Cochleariinse. 



At first sight the Cochlearius seems to represent a pigmy Balasniceps, between the 

 legs of which it can stand upright without bending its neck, and the view of their 

 "being closely related has also been urged by different authorities ; but we cannot belp 

 thinking that Professor Reinhardt was right when he opposed Professor W. K. Par- 

 ker's opinion to that effect, for, as Reinhardt remarks, even the outward likeness 

 between the two bills is, on nearer inspection, by no means so great as would appear 

 at first sight. The bill of Cochlearius is remarkably flattened, and not so much calcu- 

 lated for great strength as for great roominess ; and this is still more increased by the 

 naked dilatable skin between the branches of the lower jaw, which can be distended 

 into a complete pouch or bag hanging down as far as the throat. 



ORDER X. STEGANOPODES. 



f 



Notwithstanding the shortness of the legs and the ' Steganopodous ' character of the 

 toes,. that is, the connection of all four toes by membranes, the birds of the present 

 order are unquestionably nearly related to the Herodii. Like these, they are clesmo- 

 gnathous, and lack basipterygoid processes; "but the inner edges of the palatine bones 

 unite for a much greater distance behind the posterior nasal aperture, and a median 

 ridge is sent down from the line of junction of the palatines." Authors have been 

 equally unanimous in asserting the great homogeneity of the group, until Professor 

 St. G. Mivart, in 1877, in his valuable memoir, "On the Axial Skeleton of the Pele- 

 canidas," raised doubts as to the propriety of referring the tropic-birds and frigate- 

 birds to the Steganopodes, though it is not quite correct to say that, "according to him, 

 the tropic-birds are wrongly placed with this order." Here are his own words: 

 "Besides [JPelecanus, Sula, Phalacrocorax, and Plot us~], the two genera Fregata and 

 Pha'ethon are usually classed with them to contribute to the group of the Steganopodes. 

 But, from the point of mew here adopted (that of the postcranial part of the axial 

 skeleton only}, I have found it impossible to detect characters which seem to me good 

 and sufficient to unite such Steganopodal groups together, and at the same time divide 

 them off from other forms." It appears, however, that in the above-mentioned struc- 

 ture of the palate and the feet, which Mivart, together with the rest of the cranium 

 and the extremities, intentionally excluded from his comparison, there are characters 



