CRUSTACEA MALACOSTRACA. II. 



founded families, Apsendidjc and Tanaidai, and pointed out their distinguishing characters; he established 

 nine new genera (only five had been previously described); he enumerated nearly all species described 

 from any ocean, and he added short descriptions of all species seen b\- him, redescribing a good 

 number of species already made known and establishing twenty-three new species. He enumerated 

 in all 3 genera and 14 species of the Apseudidte, 11 genera with 46 .species of the Tauaidje, in all 

 14 genera with 60 species. Rut .\ species among the Apseudidte were noiuhia iiiida given by Norman, 

 and Sars had overlooked a single species of Apsntdcs established by Willemoes-Suhm and two species 

 of Tanaidse established respectively by Nicolet and Bate. The result is that in 1884 59 .species (not 

 counting mere synonyms) of Tanaidacea had been established. 



In 1886 G. O. Sars published his important paper: Middelhavets Saxisopoder (Isopoda cliclifrra\ 

 which contains elaborate descriptions with numerous excellent illustrations of seventeen species, all briefly 

 described but not figured by him in 1880. And in his splendid work : An Account of the Crustacea of Norway, 

 Vol.11, Isopoda (the parts on the Tanaidacea were edited in 1896—97) Sars published new descriptions and 

 eighteen plates with figures of the Norwegian Tanaidacea, in all 28 species. By the three papers enumer- 

 ated Sars has laid down a ver}- broad foundation for future study and illustration of the animals, and 

 he has done far more for the furtherance of our knowledge of the order than any other autlior. 



Since 1881 about twenty-four zoologists have published descriptions of new species, sometimes 

 besides of new genera, of Tanaidacea. Among these prominence must be given to the two English 

 zoologists A.M.Norman and T. R. R. Stebbing, because in a valuable paper (On Crustacea Isopoda... 

 1886) quoted several times in this report they gave good descriptions with numerous figures of 

 17 .species (i valid new genus), 13 of which were new and the majority even deep-sea forms; in other 

 papers each of these two authors has described and figured some other forms. — In the Challenger 

 Report Vol. XVII (1886) F. E. Beddard established 4 new genera and 10 new si^ecies, most of them 

 interesting antarctic or deep-sea forms; unfortunatel)- his figures are somewhat poor. — A. Dollfus has 

 published preliminary descriptions, with some figures, of about 14 valid new species and i new and 

 valid genus; in several papers published in later years Miss Harriet Richardson has established 2 new 

 genera and several new species, mostly American. 



In order to arrive at a fair idea of our knowledge of genera and species established before 

 the middle of 1912 I have in.spected the Zoological Records since 1877 and besides looked over the vast 

 majority of the papers. I have attempted to count the genera and species hitherto established, excluding 

 of course the synonyms, but it was impossible to arrive at absolute certainty as to tlie number of 

 species, because in a few cases it cannot be made out whether a species is valid or ought to be 

 cancelled as a synon>in, and some few species have been so poorly described that they can scarcely 

 be recognized with any certainty. But I am sure that the following numbers are nearly correct. 



The family Apseudidse comprises 8 genera: Apseudcs Leach with 28 species, Apscudopsis Norm, with 

 2 species, Parapseiides Sars with 3 species, Sphyrapus Norman with 5 species, Typhlapscndrs Bedd., Lciopiis 

 Bedd., Kalliafsetides Stebb. and Pagurapscudcs^\{\\.€[.^aoe., each with a single species. In all 42 species. 



The family Tanaidte comprises the following genera: Neotanais Bedd. (Alaotanais Norm. &: 

 Stebb.) with 5 species, Tanais H. M.-Edw. with 17 species, Leptochelia Dana with 16 species, Hcferotauais 

 G. O. S. with 9 species, Panitanais Dana with 9 species, Nototanais Richardson with 3 species, TypJdo- 



