192 CRUSTACEA MALACOSTRACA. III. 



the second, though in reality not small and easily seen when second pair are lifted; fifth pair are 

 even rather large. The genus Pleuroprion is closely allied to Arcturus ; in P. Murdochi Ben. I have 

 without difficulty found five pairs, the fifth being somewhat smaller than in Arcturus; in P. hystrix 

 G. O. S. the same number is found, but P.frigidum n. sp. differs in having only four pairs, as it is 

 easily seen that the pair of fifth legs are wanting. 



Then Astacilla. The first correct statement on the marsupial plates is due to Bonnier, who in 

 1896 described and figured four pairs in Astacilla Giardi Bonn., in 1911 established by Koehler as a 

 new genus, Arcturopsis. The last-named author examined Astacilla longicornis Sow., A. granulata G. O. S., 

 A. Deshayesii Luc., Arcturella danmoniensis Stebb. and a number of new species belonging to the same 

 genera and to two new genera; he found everywhere three pairs of lamellae belonging to second to 

 fourth pairs of legs. Stephensen (1915) found four pairs of lamellae in his AstacillaQ] Bonnieri Steph., 

 but only three pairs in A. longicornis Sow. In A. longicornis, A. granulata and in Danish specimens 

 of Arctitrella dilatata G. O. S. I have found four pairs, and the first pair, belonging to first pair of 

 legs, are somewhat small but always distinct; I am sure that the same number exists in all European 

 species of Astacilla and allied genera. 



ArcturUS Latreille. 



The material comprises only a single species, but according to Norman a second form has been 

 found near the Faeroes. 



134. Arcturus Baffin! Sabine. 



(PI. XV, fig. 5 a). 



1824. Idothea Baffini Sabine, Snppl. to the App. to Capt Parry's Voyage, p. 228; PI. I, figs. 46. 

 ! 1885. Arcturus Baffini G. O. Sars, North-Atl. Exp., Crust I, p. 97; PL IX, figs. 121. 

 ! tuberosus G. O. Sars, ibid. p. 102 ; PI. IX, fig. 22. 



1895. Baffini Ohlin, Bidrag til Kami, om Malakostrakfaunan i Baffin Bay och Smith Sound, p. 15. 



Ohlin's book contains much information on variation among specimens. -- The largest spec- 

 imen seen by me is from East Greenland, Lat 7253' N., and is 56-5 mm. long; Norman recorded a 

 specimen to be 60 mm., and Miers a specimen from Grinnell Land, at Lat. 7929' N., as being 66 mm. 

 Occurrence. Taken by the "Ingolf" at seven stations. 

 Davis Strait: Stat. 31: Lat 6635' N., Long. 5554' W., 88 fath., temp. r6; 3 spec. 



Stat 34: Lat 65i7' N., Long. 54i7' W., 55 fath.; 2 spec. 

 West of Iceland: Stat. 87: Lat 65O2' N., Long. 23s6' W., no fath.; 2 spec. 

 Between Iceland and the Faeroes: Stat 4: Lat 64O7' N., Long. ni2' W., 237 fath., temp. 2-5; 



14 spec. 

 Stat. 3: Lat. 6335' N., Long. io24' W., 272 fath., temp. 0-5; 



14 spec. 

 Stat. 2: Lat.6304'N., Long. 922' W., 262 fath., temp. 5-3; 



many specimens; most of them are young. 

 North of the Faeroes: Stat 143: Lat 62s8' N., Long. 7=09' W., 388 fath., temp. -7-0-4; 2 spec. 



