42 EEV. T. E. E. STEBBING— BISCATAX PLAiSKTON : 



are known, viz., E. nordmani Loven, M spinifera Miiller, and U. tergestina Glaus." 

 Of the last lie lias convinced himself " that it is very distinct from the other two marine 

 species, heing especially distinguished by the fact, that the exopodite of the 2 middle 

 pairs of legs carries 3 well-developed setae, a character not found in any other known 

 Evadne." Thus these three species in their chronological order offer a synoptic arrange- 

 ment easy to remember : — 



Exopodofthe f with one seta 1. E. Nordmanni,'Lo\iu. 



third pair < with two setse 2. E. spiniftra,V. Y,.Tsl\i\\ev. 



of legs. I with three setae 3. E. tergestina, Claus. 



1. Evadne Nordmanni, Loven. 



1836. Evadne Nordmanni, Loven, K. Vet.-Akad. Handlingar (Stockholm) for 1835, pp. 1-29, pi. 1. 

 1850. Evadne Nordmanni, Baird, British Entoraostraca, Ray Soc. p. 114, pi. 17. fig. 2. 

 1901. Evadne Nordmanni, Lilljeborg, Cladocera Suecise, in Nov. Act. Sc. Upsal. ser. 3, xix. p. 641, 

 pi. 86. fF. 4-17. 



This species was taken by the ' Research ' at thirty-seven Stations, the depth being 

 specified in eight cases as fathoms, and in most others as between and various depths 

 down to 100 fatboms, but it is also recorded at Station 34^ from between 750 and 500 

 fathoms, one specimen, and at Station 31 d, from between 1000 and 750 fathoms, one 

 specimen. There were about 170 specimens in all, the majority coming from nine or ten 

 of the Stations, at which the number ranged from five individuals up to (in one instance) 

 some dozens. These occurrences are discussed on p. 52. 



2. Evadne spinipera, P. E. Miiller. 



1867. Evadne spinifera, P. E. Miiller, Danmarks Cladocera, Naturhistorisk Tidsskrift, ser. 3, 

 vol. V. p. 225, pi. 6. figs. 11-13. 



The long spine at the distal apex of the organism, to which the specific name refers, is 

 an additional and very obvious character for distinguishing this from the preceding 

 species, in which the apical spine is minute and sometimes evanescent. The two species 

 may occur together, Miiller's being apparently much the rarer of the two. 



At Station 80 »2, between the surface and 25 fathoms, two specimens were taken, 

 along with several oiE. Nordmanni. At Station 31 h, between the surface and 50 fathoms, 

 several specimens were taken of E. spinifera alone. 



Occurrences : 30 m. 25 to fathoms. 2 specimens, with E. Nordmanni. 

 31 b. 50 to fathoms. Several, no E. Nordmanni. 



THYROSTRACA. 



Earn. Lepadid^. 

 Ctpris-stage op Lepas pectinata, Spengler. 



1793. Lepas pectinata, Spengler, Skrit'ter Naturliist. Selskabet, vol. ii. Heft ii. p. 106, pi. 10. fig. 2. 

 1854. Lepas pectinata, Darwin, Balauidse (Ray Society), pp. 112-114. 



1876. Lepas pectinata, Claus, Untersuchungen geneal. Grundlage des Crustaceen-Systems, pp. 84, 87, 

 pi. 16. fig. 4. 



