M. T. Thorell on the Argulida. 149 



struct the skull and dentition of this famous marsupial lion 

 (Plate XL fig. 1), which, in my opinion, was not much more 

 carnivorous than the Phalangers of the present time. 

 I also enclose drawings of sections of 



Lower incisor of Thylacoleo. . . . Fiff. 2. 



„ „ Nototherium . . Fig. 3. 



„ „ Diprotodon . . Fig. 4. 



„ „ Thylacine .... Fig. 5. 



„ „ Sarcophilus . . Fig. 6. 



Upper incisor of Felis tigris . . Fig. 7- 



Lower „ „ Fig. 8. 



showing the relative size of the teeth in these animals, and 

 proving sufficiently that the Thylacoleo was far inferior in 

 strength to a modern tiger, and no match for ponderous Dipro- 

 todons and Nototheriums. The scale of the photographed 

 fractions is in inches, the sections are of the natural size. 

 I remain. Gentlemen, 



Your most obedient Servant, 



Gerard Krefft, 

 Australian Museum, Sydney. Curator and Secretary. 



May 24, 1866. 



XXVI. — On Two European Argulidse, with Remarks on the 

 Morphology of the Argulidse and their Systematic Position, to- 

 gether with a Review of the Species of the Family at present 

 known. By T. Thorell*. 



Among the various groups which, during the last few years, have 

 attracted the special attention of zoologists, the small Crustacean 

 family of the Argulidse holds a prominent place. Long represented 

 by one species only, which is common throughout a great part 

 of Europe, and was already, before the time of Linnaeus, known as 

 Argulus foliaceus, this remarkable family has, in the course of 

 the last thirty years, received a sudden and unexpected acces- 

 sion to the number of its species. Kroyerf, whose writings are 

 the most recent upon the animals composing it, gives the number 

 of known species as thirteen, of which eight have been described 

 since the beginning of the year 1857, and amongst these the three 

 species which constitute Heller's American genus Gyropeltis. Of 

 these thirteen Argulidse, one {A. giganteus) belongs to Africa, and 

 one only [A. foliaceus) also to Europe; the remaining eleven are 

 all from America. 



* Translated, by A. O'Shaughnessy, from the GEfvers. af Kongl. Ve- 

 tensk.-Akad. Forhandlingar, 21st series, Stockholm, 1864 (communi- 

 cated 9th Dec. 1 863). 



t " Bidrag til Kundskab om Snyltekrebsene," Naturhistorisk Tidskrift, 

 3die R«kke, Bd. ii. (1863) p. 85. 



