(227 ) 



lines as in the paper on tlie Mauatpe (above quoted), indicates that this tooth 

 cannot possibly have been anterior to /«', and is probably much farther back in 

 the series, lint even if it is ni?, the four teeth behind it bring uj) the total to 

 seven as a njiuimua), while there is no indication to show tliat the number is 

 not far more, as indeed I think to be the case. The oldest specimen before me 

 has not ceased to produce fresh teeth behind, the general tooth-row has the 

 peculiar parallel-sided ness characteristic of the Manatee, and theoretically it is 

 only natural that, if the continuous growth of additional teeth gets once started, it 

 might go on throughout tlie life of the animal. 



How any more e.\act knowledge of the number of teeth actually produced 

 and shed is to be obtained I do not know, for tlie teeth are too equal-sized for 

 the method u.sed with the Manatee (and very vague then) to be of any further 

 use. The only possibility wonld be for a j'oang specimen in captivity to have 

 its most posterior tooth marked, and then a later examination would show how 

 many and at what rate further teeth came up behind the marked one. 



That a single form in the large family Macropodidae should have taken oa 

 this remarkable specialisation in tooth development is a most interesting fact, 

 and is strongly confirmatory of the views as to the non-primitiveness of the 

 Manatee's dentition put forward by Mr. Lydekker and myself in the paper above 

 referred to. 



13. Onychogale unguifera Gould. 

 ¥ 533. Brock's Creek. 



14. Trichosunis vulpecula arnliemensis Coll. 

 $ 020, 524. ? 521, 1519. Hall's Creek, 

 c? 667, 1351, 1510. South Alligator River. 



S 1040, 1043, 1047, 1155, 1352, 1353. ? 1037, 1042, lu44, 1154, 1350J 

 Eureka. 



15. Pseudochirus dahli Coll. 

 S 1150, 1152, 1153, 1154. ? 1147, 1148, 1149, 1151. Nellie Creek. 

 S 1491, 1493, 1494, 1496, 1497, 1498, 1501, 1503. ? 1354, 1490, 1492, 1495, 

 1499, 1500, 1502, 1504. South Alligator River. 



16. Petaui'us breviceps ^V'aterh. 



i 1429, 1431, 1434, 1430, 1437, 1438. ¥ 1428, 143u, 1432, 1433, 1435, 1439, 

 1440, 1509. .South Alligator River. 

 Topotypical of P. arid Gould. 



17. Perameles macrura (Jould. 

 $ 682, 1411. South Alligator River. 



Three without particulars. 



18. Perameles aurata Rams. 

 i 077, 1390. ¥ 680. South Alligator River, 

 c? 517. Hall's Creek. 

 Five skins without particulars. 

 These specimens represent a small form allied to P. obesuht, to which latter 



