Euphyllopoda G 7 



The specimens from the vicinity of Point Barrow, Alaska, collected by Mur- 

 doch in 1882 were all females and measured from 1 to 2j cm. to end of telson. 

 The great majority of the 50 specimens from July 21, carried almost ripe eggs 

 (except the youngest individuals), but none of the 15 specimens (1-lf cm. long), 

 from July 10 had any eggs. Murdoch (1885) notes, that in 1882 they were first 

 observed on July 8, but the next year ten days later ;i and these early specimens 

 were probably less than 1 cm. long, and the brood of the year. Armature and 

 shape of telson are as in the Canadian Arctic Expedition specimens of corre- 

 sponding sizes. 



The specimens from Martin point, Alaska, measured from 8| to 18 mm. 

 to end of telson; I give here (text figures 16, c) outlines of the shape of telson of 

 the two extremes of size of these animals. The armature of spines on telson of 

 the 18 mm. long specimen was as in the 12 mm. long specimen from Teller, 

 Alaska (see above), while its cercopods were 10 mm. long. Only three of the 40 

 specimens were less than 11 mm. in length; the others had shape and armature 

 of telson as in the 18 mm. long specimen or as in the two specimens from Teller. 

 When seen in the water the carapace of the living animals was spotted light 

 and dark brown (coloured like the mud-bottom of the lagoon-pond they occurred 

 in), with the paired eyes blue, lined with purple. Head and tail coloured like 

 carapace, but certain places ("snout" and underside of free tail end) with rose- 

 purple. Cercopods brown. Inner side of carapace rose-brown. Foliaceous legs 

 brown-green with pale appendages, the 11th pair of legs (female) darker green 

 and with rose, big eggs. Telson pale greenish-blue, with base of cercopods dark. 

 These Lepidurus were swimming around very actively in the shallow lagoon-pond, 

 making by movements of the foliaceous legs their characteristic long, winding 

 furrows in the mud surface; or burying themselves in the latter, so that their 

 trails were more obscure, with an animal at one end of each. Their food con- 

 sisted of the still smaller invertebrates (Daphnia pulex, Copepods, midge-larvae, 

 etc.) present in great numbers here. As I collected practically all the Lepidurus 

 I saw in this pond their size indicates that they all belong to the brood of the 

 year (1914), and thus were almost two months old. 



The specimens from Bernard harbour July 3, 1916, measured only from 3 

 to 10 mm. in length, with cercopods from 1| to 5 mm. long. As mentioned 

 p. 5 these are the youngest individuals secured during the expedition, and I 

 give here (text figure 1/) an outline (dorsal view) of telson and its armature of 

 the smallest specimen. A comparison with text figures lb, g, will show that the 

 outline of telson is more rectangular than triangular, and runs out into three 

 long spines and a very short one, while the older stages (more than -j cm. long) 

 have only ^wo .larger spines here, between which (with specimens more than 1 cm. 

 long) are found a few smaller spines. From the many American specimens I 

 have examined this seems to be a constant and characteristic armature of the 

 telson even in very big (up to 3 cm. long) individuals, while the row of tiny 

 spines on the middle of the dorsal side of telson vary in numbers from two to 

 four, as also the number of still smaller spines ^ between the terminal end of 

 telson and the cercopods. In individuals less than 3 mm. long the shape of the 

 telson is also more rectangular than triangular, and according to Sars (1896) 

 and Brehm (1911)' ends in only two well-defined spines (points). From the 

 text figures la, b, c, g, h, and Olofsson's account (1918, p. 384-86, figs. 

 18-19), it will also be seen how the outline of telson from rectangular 

 becomes triangular, and in the older individuals almost spatulate, though 

 they do not reach the maximum development in the latter direction (which 

 seems to be accompanied by a reduction in length of the spines) shown 

 by specimens from Norway (Sars, 1896, Tab. XII) .^ In color even the smallest 



' From the narrative of the expedition, it appears that the summer came later in 1883 than in 1882. 



2 These spines seem to be absent with individuals less than about 4 mm. long. 



2 See text figures Id, e (copies). 



< Data about the growth of the cercopods are given by Olofsson (1918). 



