366 DR. H. GADOW ON THE SYSTEMATIC [May 3, 



the anus : tliis is probably a character adapted to the fossorial 

 habits of the creature, a parallel case being afforded by Perameles. 

 It would be rash to infer from this similarity any special affinity 

 between these two genera. 



IV. The teeth are built after the zoophagous marsupial plan ; it 

 is, however, significant that the crowns of the teeth of the Dasyuridce, 

 and especially those of Myrmecohius, show the same type of struc- 

 ture as those of Ornithorhynchus {cf. Poulton and Leche ^). The 

 teeth are present in considerable numbers, and, with the exception 

 of a few, remain functional throughout life. There is no indication 

 whatever of their becoming superseded by a horny covering of the 

 jaws, the naso-frontal horny shield of Notoryctes being a special 

 feature which has no resemblance to, or connexion with, the covering 

 of the jaws of the Monotremata. 



The determination of the full number of teeth was wisely left in 

 abeyance by Prof. Stirling, although he suggested the following 

 formula: i. 5, c. j, p. |, wi- | = J5- The material placed in my hands 

 before the specimens were distributed to their ultimate places of 

 destination has enabled me to arrive at some interesting results. 

 For future reference and possibility of identification I append the 

 following list, the numbers being those which Prof. Stirling had en- 

 closed in the various bottles : — 



Specimen A. — Refers to the specimen figured by Stirling on 

 plate vi. of his monograph. Preparation of skull, in 

 spirit. Cambridge Museum. 



Specimen B. — Dry skull and skeleton. Cambridge Museum. 



Specimen C. — A partly dissected specimen. Roy. Coll. Surg., 

 London. 



Male I. — Spirit specimen. Nat. Hist. Mus., S. Kensington. 



Male II. „ „ Roy. Coll. Surg., London. 



Male V. ,, „ Cambridge. 



Female I. — Spirit specimen. N. H. Mus., S. Kensington. 



Female III. „ „ Stockholm Zootom. Inst. 



Female IV. „ „ Cambridge. 



The full number of teeth seems to be : i. - , c. j, pm. ^, m. 1=^0' 



Probably the two upper and the two lower premolars represent the 

 original pm. 1 and pm. 3, it being supposed that, as in DasyuridcB 

 and some other Marsupials, the original pm. 2 and 4 have been lost. 



Pm. 3 is fully developed and bicuspid in both mandibles of speci- 

 mens A and B, and in the right mandible of female I. 



Pm. 3 is reduced to a very small, short, and pointed tooth on 

 both sides in male II., left side of female IV., and right side of 

 specimen C. 



Pm. 3 is absent on both sides in male I., male V., female III, ; 

 right side of female IV. ; left side of specimen C. 



^ Poulton, Quart. Journ. Microsc. Sci. 1888. W. Leche, ' Biologiska Fore- 

 ningeus Forhandlingar,' Stockholm, 1891, iii. no. 17, pp. 136-154: " Beitrage 

 zur Auatomie des Myrmecobius fasciahis." 



