570 MR. F. E. BEDDAED OX THE ANATOMY OF [May 26, 



vulpina, no difference in this particular between the two forms 

 is there discernible. Now in Phalangista there is the typical 

 folding over of the hinder part of the alimentary tube upon the 

 anterior. The two figures, therefore, which have been referred 

 to, only hide the essential differences between the two types, 

 informing us merely of the existence in one and the absence in 

 the other of a cfecum — a fact already well known. It is interesting 

 to note that Centetes has not always this simple arrangement of 

 the gut. I found it in one example but not in another, where 

 there was one folding over, but no further specialisation. This 

 is also interesting not merely from the point of view of fixity of 

 characters, but because in the Hedgehog the gut is folded over 

 upon itself as in most mammals, and is not a simple coil on a 

 continuous mesentery *. 



I am not quite clear from his description and interpretation 

 of Zoerner's t results, whether Klaatsch places the Edentate 

 Myrmeco2)haga in the same category as Antechinomys. But I 

 imagine not, since Tarsius is described as showing " die einfachsten 

 Mesenterialverhaltnisse " among the Mammalia. In any case, 

 I can assert that some of the American Edentata also show a 

 very simple gut, comparable to that of Tarsius and Antechinomys. 

 In Myrmecojihaga jubata and Tamandua tetradactyla the gut 

 can be laid out without removal from the body in a continuous 

 loop, precisely like the figure given of the same by Mitchell %. In 

 this feature the genera mentioned are to be contrasted with 

 Dasypus and other Armadillos. There is, however, no indication 

 of the differences in the figures of Mitchell excepting, indeed, 

 that the mesocolon is drawn on one side of the colon in 

 one form, and on the other in the other types. This cannot, 

 however, imply any such difference as is here recorded, since, as 

 already referred to, the different conditions obtaining in Centetes 

 and Phalangista are indicated by a diagram which would 

 imply complete similarity, while Phalangista and Macroims are 



* It is possible, however, that Dr. Mitchell (Tr. Z. S. 1905, vol. xvii. p. 532) may 

 have forestalled me and have met with the same variation in this rather important 

 feature which I have noted above. In his " Summary of Systematic Inferences " he 



writes that " in most .... Insectivora the intestinal tract (is) suspended by 



a continuous mesentery." This would seem to imply the condition which I have 

 described above. On the other hand, he does not in the same section saj' the same 

 of the American Anteaters, which in this respect resemble Centetes, so far as one of 

 the specimens of the latter which I dissected is concerned. And again in the 

 special section dealing with mammals individuallj', Dr. Mitchell makes no mention 

 of a continuous mesentery, but remarks that ISrinaceus is practically identical with 

 Centetes. It may well be that the recollection of more than one example led to 

 these two not precisely contradictory, but not altogether concordant statements. 

 I may recall the fact that some years ago I described (Novit. Zool. vol. viii. 1901, 

 p. 91) a continuous mesentery in two other examples of Centetes ecaudattts, and did 

 not meet with the important variation recorded here. 



t "Bauund Eutwickelung des Peritoneixm &c. von einiger Edentaten," Inaug.- 

 Diss. Halle, 1881. Not seen by me. 



_t It is important to settle this matter definitely, for Flower is not conclusive in 

 his statements. On an early page of the " Lectures," already quoted, he remarks, 

 that the reptilian character of the gut is " only found among Mammals in some 

 Insectivora and insectivorous Marsupials." Later, however, he refers to it as also 

 existmg in ^Yhales and in 3Iyrmecophaga. 



