1909,] STRUCTURE OF THE LESSER ANTEATER. 687 



basilar artery with the circle of Willis. The basilar artery of 

 Myrmecojjhaga juhata is represented by Pouchet as having three 

 spaces, Avhere the artery divides and then shortly rejoins, instead 

 of the single area of this kind which exists in Tamandua and 

 which I have iignred in the paper upon the cerebral arteries of 

 mammals to which I have already referred. He also figures the 

 basilar artery as remaining of considerable calibre for two or three 

 inches down the spinal cord. The brain in my possession has not 

 a sufficiently long piece of spinal cord attached to it to show the 

 end of the wide region of the basilar artery. But it is nearly as 

 long, and reaches as far as between the influx of the last two pairs 

 of arteries figured by Pouchet. I imagine that the point where 

 the basilar artery suddenly alters its calibre and receives two 

 lateral arteries is really to be regarded as the junction of the 

 basilar with the anterior spinal, and that the two lateral arteries 

 are vertebral s. In that case the suggestion which I formerly 

 made with regard to Tamandibco will be wi-ong, and the space 

 included along the course of the basilar artery will not be due to 

 the anterior bifurcation of the anterior spinal artery to meet the 

 two vertebral arteries, such as I have figured for example in 

 Chinchilla lanigera^. There will be in both these genera 

 [Tamandua and Myrmecojjhaga) a basilar artery Avhich retains 

 either in one place only {Tamandua) or in more than one place 

 a trace of being primitively a double vessel, Pouchet finds three 

 of these double tracts of the anterior spinal t, of which he 

 represents the first as lying immediately behind the circle of 

 Willis, In my specimen the first of these double tracts lay just 

 behind the Pons Varolii, and the second, which was very incon- 

 spicuous, at the extreme end of the medulla. Just in front 

 of the first double tract arise the middle cerebellar arteries, which 

 are symmetrical. They arise in front of the sixth nerves. The 

 posterior cerebellar arteries, which are not symmetrical, lie 

 between the first and second of the duplicatures of the basilar. 

 Further back still the basilar receives two arteries on either 

 side, which anastomose as is shown in the annexed figure (text- 

 fig, 218, v). These are, as it appears to me, the vertebral veins, 

 in which case this is the end of the long basilar. 



§ Al%m,entary Canal. 



The general form of the Stomach in this Anteater is, as known, 

 like that of the Great Anteater, Myrmecophaga juhata. I may, 

 however, mention that the entire length of the stomach, measured 

 in a slightly oblique line owing to the form of the pyloric region, 

 was 85 mm., of which 35 mm. belonged to the pyloric part. The 

 breadth of the stomach — i. e., the diameter parallel with the long- 

 axis of the body — was 68 mm. The thickness of the walls of the 



* 1,00. cit. fig. 16, p. 184. 



t I hardly know wliere to delimit the basilar from the anterior spinal. 



