1900.] PROM THE FALKLAND ISLANDS. 565 



the eyes are simple. Professor Smith, in describing his Scyphacella 

 arenicola, says " eyes prominent, round," and " eyes black," a two- 

 fold notice from which so important a character as " eyes simple " 

 could scarcely have been omitted had it been applicable. The 

 figure of the species by Harger (Rep. U.S. Comm. Fisheries for 

 1878, pt. 6, pi. 1. fig. 2) shows well-developed eyes with numerous 

 components. 



G-en. Trichoniscus J. F. Brandt. 



1833. Trichoniscus, Brandt, Conspectus Crust. Oniscodorum, 

 p. 12 (Bull. Soc. Moscou, vol. vi. p. 174). 



1838. Itea, C. L. Koch, Deutschlands Crustaceen, 22 (162), 

 no. 16. 



1840. Trichoniscus, Milne-Edwards, Hist. Nat. Crust, vol. iii. 

 p. 174. 



1844. Itea, Zaddacb, Synopseos Crust. Prussicorum Prodromus, 

 p. 15. 



1853. Styloniscus (part.), Dana, U.S. Expl. Exp. vol. xiii., Crust. 

 p. 736. 



1857. Philougria, Kinahan, Nat. Hist. Rev. vol. iv. p. 281. 



1868. Philougria, Bate & Westwood, Brit. Sess.-eyed Crust. 

 vol. ii. p. 454. 



1870. Triclwniscus, Budde-Lund, Naturh. Tidsskr. ser. 3, vol. vii. 

 p. 227. 



1885. Trichoniscus, Budde-Lund, Crust. Isop. Terrestria, p. 243. 



1886. Philygria (preocc. Diptera, 1844), Thomson & Chilton, 

 Tr. New Zealand Inst. vol. xviii. p. 157. 



1886. Philygria, Chilton, ibidem, p. 159. 



1898. Trichoniscus, Sars, Crustacea of Norway, vol. ii. p. 160. 



To this genus Budde-Lund in 1 885 assigns nine species, one of 

 them being T. asper Koch, found in amber, and another the 

 Scyphacella arenicola of Smith, already referred to. He makes the 

 Trichoniscus leydiyi of Weber a synonym of his own T. albidus, but 

 this decision is not admitted by Sars. Dollfus added to the genus 

 the species chavesi in 1888, insularis in 1889, and with some 

 doubt murrayi and australis in 1890. In 1898 Sars instituted a 

 new genus, Trichoniscoides, to receive Trichoniscus albidus Budde- 

 Lund, T. leydigi Weber, and perhaps T. cavernicola Budde-Lund. 

 He does not mention Trichoniscus vividus Koch, but that species 

 should probably be transferred, as it has simple eyes ; and the most 

 prominent, though not of necessity the most important, distinction 

 of the new genus is that the eyes are simple or wholly wanting, 

 whereas in Trichoniscus they are " small, but distinct, consisting of 

 only 3 visual elements imbedded in a dark pigment." In 1885 

 Chilton described a marine species from New South Wales as 

 Philougria marina, but the eyes apparently have numerous visual 

 elements, the mandibles show no molar, and the other mouth- 

 organs are undescribed ; so that this species cannot be included in 

 Trichoniscus. In 1886 the same author described Philygria thom- 

 soni from New Zealand, and this appears to be a true Trichoniscus. 



