120 PERCY SLADEN TRUST EXPEDITION 



The Schizopod fauna of the Indian Ocean as evinced by the present collection 

 presents no very marked characteristics. No fewer than fourteen of the species of 

 Eu2Jhausiacea are common to both the Atlantic and Pacific Oceans. Of the remaining 

 eight, tw^o, Stylocheiro7i elongatum and Eajihausia hemigibba are known only from the 

 Atlantic and Indian Oceans while the remaining six are Pacific forms. Of the My- 

 sidacea, the species of Gnathophausia and Eucopia and EuchcBtomera tyinca are 

 bathypelagic species of wide distribution and the surface form, Siriella thompsoni, has 

 also an extensive range in the tropical and subtropical waters of the globe. Siriella 

 gracilis is, up till now, exclusively a Pacific species while the remainder are known only 

 from one or two records, all in the Pacific or Indian Oceans, so that their geographical 

 range cannot yet be said to be known. 



In the preparation of this report I have received much valuable help from my friend 

 Dr H. J. Hansen. Through his courtesy I was allowed to see an advance proof of his 

 Siboga report and thereby saved the trouble of describing several new species therein 

 described and enabled to work over my collections with his latest views before me. 

 Evidence of the debt I owe to Dr Hansen will be found on almost every page of this 

 report and I wish to express to him my best thanks. 



Order MYSIDACEA. 

 Sub-order LOPHOGASTRIDA. 



Family Lophogastridse. 



Genus LoPHOGASTER, M. Sars. 



1. Lophogaster typicus, M. Sars, var. 



Station*. South of the Saya de Malha Banks, 145 fms., one ovigerous female, 20 mm. 



I have compared this specimen with British examples of the species and find the 

 following small points of difference : — 



(1) The median-dorsal area of the carapace is finely punctate but there is an 

 entire absence of the coarser tubercular granules characteristic of northern specimens. 



(2) The median fork of the rostral plate is the same length as the lateral forks 

 whereas in British specimens it is slightly longer. 



(3) The rostral plate covers the greater part of the cornea of the eyes so that 

 the latter are much more hidden than in the more typical forms. It may also be noted, 

 though the character has no special importance, that the pigment of the eyes in the 

 present specimen is much paler than I have noticed in British examples of the species. 



(4) The prominent lobe on the inner distal corner of the third joint of the 

 antennular peduncle, is slightly serrate on the margin, instead of smooth. 



* The Stations where the diiFerent species were caught will be found recorded in Trans. Linn. See. London, 

 ser. 2, Zool., vol. xii. pp. 169 — 174. 



