60 SUMMARY OF CUKRENT RESEARCHES RELATING TO 



the Norwegian North Sea Expedition of 1876-78. He criticizes 

 Malmgren's method of distinguishing and delimiting genera, of 

 which he thinks he has made far too many and has used altogether 

 unimportant characters ; he points out that the pedal bristles do not 

 differ in essential matters — " the type of the bristles is the same in all 

 Polynose, with the exception of Melcenis loveni and Polynoe scolopen- 

 drina." The scales, in Hansen's opinion, are much more valuable, 

 being characteristically constant in each species, and a study of them 

 shows that Mobius and Tauber have gone too far in the opposite 

 direction of " lumjiing " Malmgren's si^ecies and genera. 



Tables of distribution are given from which it is evident that but 

 few families of Annelids are absent from the frigid area, and the 

 species are the same as those found in temperate waters ; P. globifera 

 alone indicates that its favourite, if not its sole, habitat is the cold 

 bottom strata. As it is both coloured and provided with eyes it 

 throws much doubt on the hypothesis of Ehlers that the deep-sea 

 fauna has its numbers recruited from forms living in shallower water. 

 Neither depth nor temperatui-e appear to affect the development of 

 Annelids. A number of new species are described. 



Eclipidrilidse.* — G. Eisen gives an account of a new Oligochaete 

 which he discovered in 1878 in the Sierra Nevada ; the specimens 

 that he took down with him dying before he reached a Microscope, he 

 scaled the mountains again in the succeeding year, so as to be able to 

 make an investigation into the characters of its cii'culatory system on 

 the spot. 



The vascular system consists of two primary longitudinal vessels, 

 of which the dorsal pulsates and is of nearly the same size as the 

 ventral ; there are secondary perigastric and gastric vessels, and the 

 former are either connecting or free. The former of these are foimd in 

 the anterior segments of the body, and connect the two primary vessels ; 

 the two last are longer than the rest, and suj)ply the generative 

 organs ; they are none of them dilated into hearts, but they all 

 pulsate slightly. The free perigastric vessels are placed in the more 

 posterior segments, and are derived from the dorsal vessel ; they 

 pulsate slightly, and their inner end is free. The gastric vessels are 

 found in the segments in which there are no perigastrics, and connect 

 the dorsal and ventral vessels. Resembling, therefore, on the whole 

 the vascular system of Tubificidse and Lumbriculidfe, that of the 

 Eclipidrilidse is distinguished by never having gastric and perigastric 

 vessels in the same segment. The blood is of a reddish yellow 

 colour. The digestive system is a simple duct, just as in the 

 Tubificidae. 



The testes form two saccular amorjAous bodies in the 9th-13th 

 segments, one on each side of the body ; they contain numerous cysts 

 of spermatozoa, but no free ones, and each cyst forms a globular body, 

 with a round wedge-shaped tail ; it is always covered by globules, 

 which are either partly separate, or which run together forming 

 beautifully elevated ridges, which in regularity and beauty can only 



* Nova Acta Reg. Soc. Upsal., xi. (1881) 10 pp. (2 pis.). 



