6 Cl. O. Sars. 



Lepidurus viridulus, Täte, as represented by Brady, is most 

 certainly only a mal-formed and badly preserved specimen of 

 the present species, and I am also of the opinion, that the 

 New Zealand form, Lepidurus Kirhii Thomson, is the very 

 same species. Whether the Australian form should also be 

 regarded as identical with the European form, Lepidurus pro- 

 ductus Bosq., seems to me, on the other hand, more questio- 

 nable. There is certainly a very great resemblance between 

 the two; but the widely remote occurrence of these forms would 

 indeed seem to forbid such an identification. Yet a careful 

 comparison between these 2 forms, both as to their external and 

 anatomical characters, would indeed be highly desirable. From 

 the arctic form, i. glacialis, which I have myself had an op- 

 portunity of examining in detail, the present species is at once 

 distinguished both by its much larger size and by the shal- 

 lower posterior emargination of the carapace, as also by the 

 different form and armature of the caudal lamella, and the 

 more elongated endites of the 1st pair of legs. 



Description of the female. 



The length of the largest specimens, measured from the 

 front edge of the carapace to the tip of caudal lamella, amounts 

 to 38 mm., or about l^/a inches. 



• The carapace is comparatively large and, when seen from 

 above (fig. 1), of a rather regular oval form, with the edges 

 quite evenly curved both in front and laterally. Behind, it 

 exhibits a comparatively shallow emargination, defined on 

 each side by a triangularly projecting lobe, and from within this 

 emargination the posterior part of the body is seen projecting. 

 In its anterior part the usual cervical sulcus is seen, and within it 

 the mandibular segement is marked off as a transverse promin- 

 ence. In front of the latter, the cephalic part of the carapace 

 forms in the middle an obtusely rounded prominence, on the tip 



