54 Prof. Ehlers on the Vermes 



point where the inner marginal part passes into the hinder, a 

 darker spot of the same colour projecting a little towards the 

 light central surface ; the ground-surface of the elytra is in 

 other respects of the same pearl-grey as in the preceding race. 

 The ventral surface and the rami are colourless ; the dorsal 

 surface of each segment bears a sharply bounded banded 

 marking of dark greyish-green colour, the arrangement of 

 which in general is such that a broad transverse band runs in 

 the middle of each segment, and is continued, either of the 

 same width qy: becoming narrower, to the apices of the dark- 

 coloured elytrophora ; before and behind this band there is a 

 concolorous narrower one, which is separated from the main 

 band by a fine line of the pale ground-colom', and bounded 

 anteriorly or posteriorly by the colourless margin of the seg- 

 ment. If the pigmentation extends further, the whole dorsal 

 surface of the segment may appear colom-ed, with the excep- 

 tion of a fine pale line, running in front and behind, near and 

 parallel to the colourless margins of the segment. If the 

 pattern is less distinctly marked, it resembles the dorsal pat- 

 tern of an Harmothoe imbricata ; if it is strong, it reminds one 

 of the coloration of Melcenis Loveni (Malmgr.). Two large 

 specimens with strong coloration, now before me, were so 

 much the more like Melcenis Loveni, because they bore quite 

 small, and evidently newly formed, elytra, and the number of 

 setge in the upper branch of the ramus was considerably dimi- 

 nished. The animals of this form attained larger dimensions 

 than the brown ones ; the largest was 46 millims. in length, 

 and, with the setae, 24 millims. in breadth. 



These varieties of Antinoe Sarsii from the Spitzbergen Sea 

 acquire a special interest when we compare them with the 

 variety living in the Baltic. According to Malmgren, this 

 smaller Baltic form possesses a greenish dorsal coloration and 

 elytra with brownish margins ; it thus occupies a middle place 

 between the two races from Spitzbergen now before me, of 

 which one possesses only greenish-grey, and the other only 

 brownish pigment. 



Malmgren has already shown that Antinoe Sarsii, which 

 occurs only in the northern part of the Gulf of Bothnia, is to be 

 numbered among those animals the limited diffusion of which 

 here is explained by Lov^n's view, according to which the 

 Baltic was united with the Arctic Sea, in the glacial period, 

 through the White Sea and Bay of Ladoga. If the present 

 form of Antinoe Sarsii in the Baltic differs from its relatives 

 at Spitzbergen by its smaller size, this is in accordance with 

 the observation repeatedly made that marine animals diminish 

 in size during adaptation to less saline water, as in the present 

 case the water of the Baltic is ; but with regard to the pecu- 



