1889.] MR. W. K. PARKER ON STEATORNIS CARIPENSIS. 175 



seen how Bucerine the palate is. This isomorphism, however, has 

 to be taken for what it is worth ; it is very limited, and in the great 

 Cuculine group (Coccygomorphse) we everywhere meet with charac- 

 ters in one Family that correspond in some degree with those in 

 another, where everything else is very unlike. This is to be noted in 

 the contrast seen between the dorsal vertebrae of the Bucerotidae and 

 those of Steatornis. In the former they are cylindroidal, and very 

 broad, widened, and flat below; those of the latter runinto a mere keel. 

 Also, in the Bucerotidse the spines in the dorsals form a feeble saddle- 

 baclced series, having a concave general outline ; in Steatornis they 

 form a strong straight series, and the interspaces between the spines 

 are very small. In a New-World Kingfisher {Cenjle aJcijon) the 

 hinder dorsal centra make a great approach to those of Steatornis, 

 without, however, being opisthoccelous. 



The peculiarity just referred to in the ribs is their great breadth 

 above, their narrowness below, and the low position of the uncinate 

 processes (p.u.). The second pair are the widest ; they are 6 millim. 

 across for some distance below the tuberculum, and only 3 millim. 

 near the lower condvle ; the processus uncinatus is only ir5 millim. 

 at its base, above that, the condyle is 13 millim. long, and has an 

 average breadth of 2-5 miUim. The 1st sacral has a pair of ribs 

 which have a sternal piece, imperfect, but 17 millim. long. The 1st 

 dorsal sternal piece is 14 miUim., the last 28 miUim. long; they 

 have an average width of 2 millim. The sacral vertehrce and the 

 whole pelvis (Plate XIX. figs, 2, 3, and Plate XX. fig. 6) are very 

 much like those oiCeryle alcijon, — the Kingfisher whose dorsals show 

 a tendency to the opisthoccelous character, and have deep, concave- 

 sided dorsal centra, with long, basally-dilated, inferior spines. As 

 in that bird and the Hornbills the sacrum is completely ankylosed 

 to the iliac bones, even in the young bird of the first year. This 

 perfect union of the lateral with the median elements of the pelvis 

 is seen in the Common Cuckoo (Cucubts canorus) in young birds of 

 the first summer, but it is not seen in Cocci/zus nor in Saurothera, 

 even in old birds, so that this character must be a thing dependent 

 upon conditions, being so variable in nearly related types. The most 

 remarkable thing of all, however, is this, namely, that whilst these 

 parts are completely ankylosed in the young Cuckoo, in the hinder 

 half of the sacrum of an old bird the sutures are quite distinct. This 

 is a phenomenon of the same nature as the re-segmentation in the 

 adult of the last sacral of the young bird to increase the number of 

 the free caudal vertebrae, a very common thing in the higher birds \ 



The first three sacrals are not yet ankylosed by their centra in 

 the youngest specimen, and the 1st only is partly distinct in an 



• I cannot leave this part of my description witbout remarking that this 

 must be part of some general law with regard to the evolution of the higher 

 kinds of birds. Intense ossification is the thing we are most familiar with in 

 the osteology of birds, as compared with other Vertebrata. And yet the birds 

 that are manifestly mos/ archaic are often most intensely ossified : thus, to take 

 a single fact, an archaic bird is often, not always, desmognathous, whilst a 

 more specialized, newer, and nobler bird of the same family will be schizo- 

 gnathous. 



