GENUS OF TERRESTRIAL ISOPODA. 437 



I recognise six species — two from South Africa, two from New Zealiind 

 (one of which is found also in South America) ^ another species from 

 St. Paul's Island in the Indian Ocean, and the sixth from the East Coast 

 of Australia. 



In his last Hevision of the Terrestrial Isopoda, Budde-Lund (1904) placed 

 Deto under a subfamily Detonince of the Oniscidse, and Stebbing (1910, 

 p. 444) has since raised this to the rank of a family. In 1901 I placed the 

 genera Scyphax, Dana, Actcccia, Dana, and Scf/phoniscus, Chilton, under 

 Scyphacidee, a family distinct from, though closely allied to, the Oniscidse ; 

 in this family I had also included Adcecia aucldandioi (G. M. Thomson), of 

 which I had been able to examine a single female specimen, but whose 

 affinities to Deto I had not then recognised. An examination of the whole 

 of the species shows that Deto would readily come under this family as then 

 defined by me_, and the genera mentioned seem, to be sufficiently closely 

 allied to justify us in placing them in one family rather than in establishing 

 three or four separate families or subfamilies for their reception. 



I shall now give diagnoses of the genus and of the different species of 

 Deto, reserving some general remarks on the genus for the conclusion 

 of the paper. 



Family SCYPHACID^. 



Scyphacina, Dana, 1853, p. 716. 

 Scyphacidcs, Chilton, 1901, p. 121. 

 „ Richardson, 1905, p. 671. 



The description of this family given in 1901 was as follows : — " Mandibles 

 without molar tubercle, its place being taken b}^ a tuft of long stiff setse or 

 bristles ; inner lobe of first maxilla with two plumose bristles ; maxillipeds 

 with the terminal joints fairly well developed, lamellar, longer than the 

 masticatory lobe ; external male organ single." 



The characters of the genus Deto come well within this definition. 



Genus Deto, Guerin, 1834. 



Deto, Guerin, 1836, notice 21, p. 1. 



„ Milne-Edwards, 1840, vol. iii. p. 174. 



„ Budde-Lund, 1879, p, 9. 



„ Budde-Lund, 1885, p. 233. 



„ Budde-Lund, 1906, p. 84. 



„ Chilton, 1909, p. 666. 



„ Stabbing, 1910, p. 444. 



The generic description given by Budde-Lund in 1885 w^as based on the 

 examination of imperfect specimens of two species only; in 190(3, having 

 been able to examine additional specimens, including well-preserved specimens 



