DETO, A SUBANTARCTIC GENUS OF TERRESTRIAL ISOPODA. 435 



Deto, a Subantarctic Genus of Terrestrial Isopoda. By Charles Chilton, 

 M.A., D.Sc, LL.D., M.B., CM., F.L.S., Professor of Biologj, Can- 

 terbury College, New Zealand. 



(Plates 39 & 40.) 



[Real 4tli June, 1914] 



Contents. 



Page 



Page 



Introductory and Historical 435 



Family Scypbacidte 437 



Genus Deto, diagnosis and synopsis 



of species 438 



1. D. echinnta, Guerin 440 



2. D. acinosa, Uudde-Lund 441 



3. D. «r??i«te,Budde-Lund 443 



Genus Deio (continued). 



4. D. marina (Chilton) 444 



5. D. aucklayidice (G. M. Thomson) 445 



6. D. bucciilenta (Nicolet) 449 



General Remarks 453 



Bibliography 454 



Description of Plates 455 



Introductory and Historical. 

 The genus Deto was established by Guerin in 1836 for a species, 

 D. ecUnata, which was vaguely described as having been found in the East 

 by Olivier ; the chief character of the genus was that the antennse were 

 composed of nine joints, i. e. five in the peduncle and four in the flagellum, 

 and was thus distinguished from Oniscus, which had three joints in the 

 flagellum, and from Porcellio, which had only two. The genus was after- 

 wards mentioned by Milne-Edwards (1840) * and Dana (1853), but no 

 further addition to our knowledge of it was made for many years. In 1843 

 Krauss included the species in his list of South African Crustacea as having 

 been collected on the sea-shore at Table Bay, and later on it was collected at 

 the Cape by the ' Novara ' Expedition. Besides the type-species, two others 

 were afterwards described under this genus, namely, D. spinicornis^ Brandt 

 from the southern shores of the Sea of Okhotsk, and T. lohitei, Kinahan, of 

 unknown locality ; it appears likely, however, that the latter species is 

 identical with the type-species. In 1879 Budde-Lund in his 'Prospectus 

 generum specierumque Crustaceorum Isopodum Terrestrium,' gave the 

 genus with these three species, and thinking that Deto spinicornis was 

 rightly referred to the genus, he placed the genus under his second family 

 Liyice. Later on, however (1885), finding, on an examination of the poorly 

 preserved specimens in the St. Petersburg Museum, that D. spinicornis 

 should probably be referred to Triclioniscus, and having had an opportunity 

 of examining two species really belonging to Deto, he came to the conclusion 

 that the genus should come near to Oniscus, and that it is perhaps not 



* The references are made by the year of publication to the bibliographical list on 

 pp. 454, 455. 



35* 



