No. IX.— ON THE MYSIDACEA AND EUPHAUSIACEA COLLECTED 

 IN THE INDIAN OCEAN DURING 1905. 



By W. M. Tatteesall, D.Sc, Keeper of the Manchester Museum. 



(Plates 6 and 7.) 

 (Communicated by Prof. J. Stanley Gardiner, M.A., F.R.S., F.L.S.) 



Read 2nd March, 1911. 



I AM indebted to the courtesy of Professor Stanley Gardiner for the opportunity of 

 examining the collection of Schizopoda, with which the following account deals, made by 

 him in the Indian Ocean in the year 1905. 



The collection is by far the largest individvial one made in the Indian Ocean and 

 is a valuable addition to our knowledge of the Schizopod fauna of that sea. It contains 

 thirty-six species as against a total of thirty-two species, the sum of the results of 

 previous observations on this group of Crustacea in that locality. Only ten of the 

 species here recorded have hitherto been noted from the Indian Ocean so that the present 

 collection adds twenty-six species to its fauna and brings the total number of species of 

 Schizopoda known from these waters up to fifty-eight. 



Much, however, still remains to be done, especially with regard to the Mysidacea, 

 before the Schizopod fauna of the Indian Ocean can be said to be completely or even 

 nearly elucidated. One had hoped that Professor Gardiner's collection would have 

 thrown considerable light on the bottom living species of tropical Mysidacea but it 

 contained only one specimen, of a known species, of forms which fall into that category*. 



Of pelagic Mysidacea the Scalark captured fourteen species, two of which are new 

 to science and belong to two genera recently instituted by Hansen for Sihoya specimens. 

 Of the remainder, four are known only from the Sihoya material while a fifth has hitherto 

 only been captured by the Valdivict expedition, naturally enough in the same locality as 

 by the Sealark. 



As regards the Euphaiisiacea, Professor Gardiner was distinctly more successful. In 

 all twenty-two species were collected, a luimber which compares very favourably with the 

 total of twenty-five taken by the Siboya expedition. 



* [We intentionally ran nioxt of our dredgings on the edges of the banks wo visited, while on their 

 surfaces we were particularly investigating upgrowing banks. The ground was generally rough and unsuitable 

 for catching Mysidacea. Our dredges also were built so as to bite deeply into the ground. In spite of these 

 facts 1 cannot understand the absence of Mysidacea unless they are really scarce on these oceanic coral banks. 

 J. Stanley Gardiner.] 



