Annelids from the Danmark Expedition. 425 



pelagicalh] at the side of the ship on the 12th and 18th of September 

 1907, and for the rest, that they were taken pelaglcalhj under the ice 

 or frozen-in in this, on the 24th of September 1906. On looking 

 through the Danmark's Journal, further, I find the following remarks 

 by the zoologist of the Expedition, which I cite in extenso. 



"Many bristle-worms are met with frozen-in in the ice; they lie 

 right on the top or as much as ca. 3 inches down ; in the first case 

 they are as a rule dead, in the last case the water round about 

 them is not frozen, even though it may be so above them; they 

 then lie and twist about in a hole with water or broken ice when 

 the overlying ice is removed; the same worms are also seen very 

 commonly wriggling about in all layers of water under the ice, or 

 they are attached to the underside of this by their one end; they col- 

 lect especially at places where refuse from the ship is frozen-in in 

 the ice; or they attach themselves in the same manner to the body 

 of the ship and wriggle along this". 



This account of these animals in no way agrees with the pictures 

 we are accustomed to form regarding the mode of life of the Scali- 

 bregma; they live usually in the sea-bottom, in a similar manner to 

 Arenicola and dig down to a depth of ca. "2 feet", as Danielssen 

 already remarked. That they are able to swim, however, is also 

 noted by the same author, as he writes, that they swim "with the 

 greatest activity and move about whilst swimming exactly like a leech". 



The phenomenon described by the zoologist of the Danmark 

 Expedition cannot, naturally, be regarded as an ordinary chance 

 case of swimming. We have here innumerable individuals leaving 

 their usual abode and moving up into the upper water-layers, and 

 on examining them we find, in the first place, that they are found 

 to be streaming full of sexual products, and in the second place 

 to be transformed in a suitable manner, as they are provided with 

 long, sлvimming bristles. The phenomenon is thus similar to what 

 we know already in the epitokous forms of other Annelid groups. 

 That no eyes seem to be formed in Scalibregma, is probably not so 

 important and possibly something characteristic of this form; I may 

 just mention, however, that some pigment spots occur in a straight 

 row on the upper side of the dorsal cirri, spots which however are 

 also found in the typical, untransformed form of S. inflatum. 



It is my belief, therefore, that Michaelsen's var. corethrnra is not 

 a variety, but the epitokous, sexually altered form of Scalibregma 

 inflatum. 



The phenomenon the zoologist of the Danmark Expedition has 

 observed, indicates that the sexual transformation and spawning 



