THE GKEAT ANTEATEB. 309 



As in Mams tridentata as described by Rapp *, the chevron bones in 

 the tail contain a curious caudal rete mirabile, composed of both venous 

 and arterial elements, which completely surrounds, as in a sheath, a 

 central artery of large size, which is the direct continuation onwards of 

 the abdominal aorta, and gives off here no branches at all to the rete. 

 The arterial elements of this rete are derived from several small trunks 

 on each side, which arise from the caudal artery beyond the origin of 

 the internal iliacs, and then break up into a number of more or less 

 parallel, rarely anastomosing, branches, mixed up with which are similar 

 venous trunks. A similar rete occurs in Tamandua, and also, as 1 

 am informed by Prof. Flower, in the Spider Monkeys of the genus 

 Ateles. 



The paired eyelids are very small, and hardly exist as special organs ; 

 there are no eyelashes. The third eyelid, on the other hand, is very 

 large and well developed. It contains a large cartilage of concavo- 

 convex shape ; on the internal surface of this eyelid, just below the 

 inferior border of the contained cartilage, opens the minute aperture of 

 the Harderian gland, which is very large, almost completely surrounding 

 the orbit, and concealing the much more minute lachrymal gland. As 

 described and figured by Pouchet, it consists of three chief lobes. 



As already suggested by Chatin, I have little doubt that it is the 

 Harderian gland that has been described by Cuvier (Anat. Comp. 2ine 

 ed. iv. part 1, pp. 430, 431) and Owen (I. c. pi. xl. fig. 36) in Cycloturus 

 as a salivary gland opening into the mouth. 



Clavicles are frequently supposed to be absent in the Great Anteater, P. Z. S. 1882. 

 though present as rudiments in Tamandua, and well developed in p ' 

 Cycloturus t. 



In the larger specimen of the two examined by me I find, however, 

 a distinct one present on each side, lying in the muscles, about an inch 

 long, nearly straight, of flattened form, with one end cylindrical. Similar 

 ones were also present, closely attached to the sternum, but of smaller 

 size, in the second specimen. Eapp (1. c. p. 40) found a rudimentary 

 cartilaginous one in Myrmecophaga, though he (erroneously) denies one 

 to Tamandua. There is also an accessory ossicle developed at the head 

 of the fibula, as in some of the fossil forms. 



In the anterior comu of the hyoid bone, I find in both specimens three 

 distinct ossifications J. The proximal of these is a small nodule of bone, 

 3 inch long, articulating below with the basihyal ; it is called the 



* L. c. p. 92. 



t ' Osteology of the Mammalia,' by W. H. Flower, p. 235 : London, 1876. 

 J The accounts given by different authors of the composition of the hyoid bones in 

 the Anteaters differ considerably infer se. Cf. Pouchet, ' Memoires,' pp. 93-95. 



