Natural History of East FtnmarJc. 23 



Dactylopus Strdmii (Baird), var. arcticuSy T. Sott. 

 (PI. IV. figs. 1-7.) 



1899. Bactyhpus Siromii (Baird), var. arcticus, T. Scott, " Crust, from 

 Franz-Josef Land," Journ. Linn. Soc, Zool. vol. xxvii. p. 106, pi. v. 

 figs. 11-17. 



Several female specimens of this variety were obtained in 

 gatherings from Bog Fiord and Vadso Sound. In this variety 

 the antennules are nine-jointed ; the posterior foot-jaws appear 

 to be more hirsute than in the typical form, and the first and 

 fifth thoracic feet are somewhat similar to the same appendages 

 in D. si77iiliSj Claus. 



One or two male specimens apparently belonging to the 

 same variety were also obtained in the gathering from Bog 

 Fiord, and as no special mention was made to the male form 

 in the original description of the variety in my *' Report on 

 the Franz- Josef Land Crustacea " referred to above, I will 

 here glance briefly at a few of the more important characters 

 by which it is distinguished from the female. It differs from 

 the female in having the antennules modified as shown in 

 the drawing (fig. 2). The second pair of thoracic feet have 

 the inner branches apparently two-jointed ; the first joint is 

 very short, but the second is elongated and narrow except at 

 the base, where it is dilated on the outer aspect ; this joint, 

 whicli reaches to near the end of the outer branches, bears on 

 the dilated basal part a stout spine-like appendage that 

 readies to the end of the joint, as shown in the drawing 

 (fig. 5), while the end of the joint itself terminates in what 

 looks like a recurved bifid process, which has one branch of 

 the fork elongated and slender, extending to near the base of 

 the joint, but the other branch is short ; the spines on the 

 outer distal angles of the joints of the outer branches of the 

 second pair of feet are also moderately stout — proportionally 

 more so than in the female. 



The fifth feet (fig. 6) are small ; the inner part of the basal 

 joint, which is only slightly produced and rounded, is armed 

 with three small spines ; tlie secondary joint is broadly ovate 

 and is furnished with a few marginal and terminal setae, as 

 shown by the figure. 



The specimen represented by the drawing (fig. 1) measured 

 about a millimetre in length. 



Genus Thalestris, Claus, 18G3. 

 Thalestris hefgoJandica, Claus. 



1863. Thalestris hehjolandica, Claus, Die frei lebenden Copepoden, 

 p. 131, t. xvii. figs. 12-21. 



