THE VOYAGE OF THE ' CHALLENGER.' 439 



/. Fasciculus of patagial tendons continued on to ulnar fascia ; a, a'. Ossicles 

 developed at origin of the extensor metacarpi radialis longior ; t.p' . (in fig. 5). 

 Special slip from patagial tendons to deep belly of extensor metacarpi radialis 

 longior. 

 Fig. 3. The same in (Estrelata brevirostris. 



4. The same in Diomedea exulans. An arrow is passed between the twin tendons 

 of origin of the superficial part of the extensor metacarpi radialis longior. 



PLATE XX. 



Fig. 1. View of superficial muscles of right thigh of Majaqueus aquinoctialis ; P. Exp. vol. iv. 

 Pelvis; s. Sartorius; gl. 1. Glutens primus; g. Gastrocnemius ; b. Biceps; pt. xi. pi. v. 

 s.t. Semirtendinosus ; s.m. Semi-membranosus. 



2. View of deeper thigh-muscles of the same bird ; the glutens primus, biceps, and 



gastrocnemius (g'.) muscles cut and reflected to show the deeper parts. 

 Lettering as above ; also b'. cut end of biceps passing through the tendinous 

 loop formed by the origin of the gastrocnemius ; f.c. Femoro-caudal muscle 

 a.f.c. Its accessory head; o.e. Obturator externus; add. Adductor muscles- 

 f.v. Femoral vein ; s.c. Sciatic nerve and artery ; o.g. Oil-gland. 



3. The same parts in Oceanites oceanicus ; a.s.t. Accessory semi-tendinosiis muscle ; 



Pb. Pubis ; 7?. Eectrices. 



4. Dissection of thigh of Pelecanozdes, to show the absence of the accessory femoro- 



caudal muscle, and the abnormal course of the femoral vein, this passing 

 over, instead of under, the femoro-caudal muscle ; o.i. Obturator internus 

 gl. Glutei. 



PLATE XXI. 2 bid. pi. vi. 



Fig. 1. Left humerus of Majaqueus cequinoctialis, from above. 



2. Proximal, and fig. 3, distal extremities of the same bone, inferior surface. 



4. Vomer with the ascending plate, anchylosed to it, of the palatine bones of 



Diomedea exulans, from above. 



5. The same, fr jm the side. 



6. Proximal end of right tibia of Ossifraga gigantea, to show the cnemial crest. 



7. Left uncinate bone (" os crochu " of Reinhardt) from behind, of Thalassiarche 



culminata. 



8. The same of Pkoebetria fuliginota* 



PLATE XXII. 



Fig. 1. Skull of (Estrelata lessoni, viewed from the side. All the figures are of the 

 natural size. 



2. The same, from below. 



3. The same, from above. 



4. Skull of Prion vittatus, from below. 



5. Pelvis, seen from the side, of Majaqueus cequinoctialis. 



6. Hallux of Ossifraga, with its metatarsal. The single phalanx of which it 



consists is vertically bisected, to show the hollow interior. 



PLATE XXIII. 



Fig. 1. Sternum, with coracoids and furcula, of Thalassiarche melanophrys, from in 

 front. Reduced. 



2. The same, from the side. 



3. Sternum and pectoral arch of Petecanotdes urinatrix, from in front. 



4. The same, from the side. 



