Remains of an extinct gigantic Bird. 329 



even iu the immediate vicinity of his own house at Lagoa 

 Santa. His opinion that the fossil bird was generically 

 different from Cariama, and formed a lost link between 

 it and Pulamedea, was. founded not only on the difference 

 which he perceived between the tibia of the former and that 

 of the supposed- gigantic Alectorid, but also, and perhaps 

 mainly, on the consideration that, if the before-mentioned 

 toe-bone also belonged to that bird, it must have had much 

 longer toes than Cariama, of which the short toes had occa- 

 sioned the generic name Microdactylus, bestowed upon it 

 by Geoff roy St.-Hilaire. 



The fossil bone-fragment agrees so accurately with the 

 metatarsus of Rhea in size and proportion, that Lund began 

 his examination of it by comparing it with this last bone ; but 

 he did not oliserve any further similarity between them. In 

 Rhea the anterior upper end of the metatarsal exhibits a 

 deep, rather elongated, elliptical groove, which at its bottom 

 branches off into two smaller fissures opening on the posterior 

 surface of the bone. Both these fissures are remains of the 

 original division between the three coalescent "metatarsals ; 

 and the groove in front is caused by the middle metatarsal 

 being situated a little behind its two neighbours at the upper 

 end, while at the distal extremity it advances forwards, so as to 

 be not only on a level with the lateral bones but even a little in 

 front of them. The fragment of the fossil metatarsus seems at 

 first sight different, as may be observed in the annexed illus- 

 tration (fig. ] , p. 330) . The groove on the front surface is less 

 deep and less sharply defined ; the two fissures at the bottom 

 appear like small holes, each scarcely larger than a pin^s 

 head, and open on the posterior surface of the bone a little 

 more distant from each other. Besides this, the front surface 

 of the bone exhibits a swelling or knob nearly an inch long, 

 pointed at the lower end, and situated in the groove on the 

 front side of the bone below the fossa above mentioned. 



The preceding description of the appearance of this bone in 

 Rhea, however, is made from that of a young bird. The bone 

 is certainly 370 millim. long, and is quite as large as that of 

 many a full-grown bird ; but that portion of the tarsus which 



SER. IV. VOL. VI. z 



