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Show 180 MR. W. K. PARKER ON STEATORNIS CARIPENSIS. [Apr. 2, The three metacarpals (mt.c1, mt.c2, mt.c3) form together the usual main part of the manus; the inteiosseous space is large and uncovered above. The single phalanx of the 1st digit (dg.1) has no rudiment of a second joint; the distal phalanx of the 2nd (dg.2) has a small seed-shaped remnant of the ungual phalanx; the penultimate or 2nd phalanx of the 2nd digit is slightly longer and also narrower than the phalanx of the 1st digit. The single phalanx of the 3rd digit is the least of the three; it shows no signs of a second joint. The oblong proximal phalanx of the 2nd digit has a slight perforation in its thin dilated distal part. Above, returning to the head of the manus, I find a considerable thickening of the projecting shoulder of the 1st metacarpal. Also, on the extensor face of the 2nd metacarpal (close to the top of the interosseous space) there is an oval elevation 2 millim. long, due to the presence in the embryo of an intercalary metacarpal (mt.c.2'). Also, on the flexor face of the 3rd metacarpal, above the interosseous space there is a similar but less-marked elevation, which is possibly due to a rudiment of the 4th digit; as a cartilage it is very constant in several families of birds in an early stage. Large as these wings are, they nevertheless suggest the idea of feebleness; they are like the bones of a bed-ridden person, slender, smooth, and very light; is not this due to the extremely torpid habits of the bird, which only spends a very limited time in any active exercise ? that exercise being simply eating. The extreme fatness of this bird favours this view of the case. VI. The Hip-girdle and Hind LAmbs. A few measurements will show the special form of the pelvis in this type (Plate XIX. figs. 2, 3, and Plate X X . fig. 6 ) ; that part can now be studied as a whole-the hip-bones and sacrum together. This pelvis may be compared with that of Ceryle alcyon aud Caprimulgus europceus; it is most like that of the former, and has a rudiment of the peculiar spur seen on the side of the pre-ilium in Kingfishers ; it is very wide. In Caprimulgus and Podargus the pelvis is narrower. Length of pre-ilium. millim. Ceryle 17*5 Caprimulgus .. 15*5 Steatornis .... 25 The width across the pubis, below the greatest interpubic breadth, is, in Ceryle 33 millim., in Caprimulgus 23 millim., and in Steatornis 53 millim. One thing to be noticed is, that whilst in many Cuculines the "pre-pubic spike" is absent, e.g. in the Alcedinidae and Caprimulgidae Length of post-ilium. millim. 16*5 10-5 34 Breadth across pre-ilium. millim. 16 10 30 Breadth across tro> chanters. millim. 28*5 21*5 48 |
