ANTINOE SARSL 367 



in profile occupy only about half the bristle, the inferior half being thus smooth and 

 translucent. Only a minute portion of the tip is bare. Yentrally are a series of slender 

 bristles, with long spinous regions and capillary extremities. 



In the typical foot (Plate XXXI, fig. 2) the dorsal spine is still very prominent, and 

 the bristles are long, slightly curved, and with a moderately acute tip. The spinous 

 rows are distinct, and leave only a very short portion of the tip bare (Plate XL, fig. 7). 

 The ventral are slender, elongate, with long spinous regions and remarkably attenuate 

 tips, which form long hair-like processes (Plate XL, fig. 8). The foot has a long process 

 for the spine superiorly. In the terminal segments the character of the bristles alters 

 little, except as regards size. 



In the Canadian examples thecate Infusoria are common on the dorsal bristles, 

 and, in some, Loxosomx. Infusoria also frequent the British form, and a cluster occurs 

 in one on the projecting spine of the ventral division of the foot. 



The dorsal cirri are long and tapering, with a filiform tip, while the surface has 

 numerous short clavate cilia. The ventral cirrus is subulate and rather Ions' and 

 tapering, with numerous short clavate cilia. 



In certain respects, e. g. the slenderness of the ventral bristles in comparison with 

 the dorsal, and in the clearly separated rows of spines, Antinoe approaches Evame. 



Reproduction. — None of the specimens give any light on this process. 



Habits. — So far as present knowledge goes, this species would seem to frequent 

 deep water only. 



Ehlers (1871), in his account of the Spitzbergen annelids, gives a very interesting 

 description of two well-marked colour-varieties of this species. The more abundant 

 form presents the brown coloration which Malmgren states distinguishes the Spitz- 

 bergen from the Baltic form. In the other the scales are bordered with greenish-grey 

 on the inner and posterior margins, with a darker spot at their junction, the ventral 

 surface and feet being colourless. The dorsal surface of each segment is banded with 

 greyish-green, the pigment being variously developed in different examples. This 

 variety attains even larger dimensions than the first, viz. 46 mm. in length and 

 24 mm. in breadth, as against 35 mm. and 17 mm. He contrasts these two varieties 

 with that now living in the Baltic, which is smaller, possesses a greenish dorsal 

 coloration, and scales with brownish margins, — that is, it has an intermediate position. 

 He is of opinion that it has retained, since the glacial period (when the Baltic was 

 united with the Arctic Sea), the original coloration, from which the two races in the 

 Spitzbergen Sea have been developed by differentiation. 



Ehlers found a Nucula 8 mm. by 6 mm., and 4 mm. in thickness, in the intestine of 

 one of the largest greyish-green varieties. The same author (1875) describes it from 

 the ' Porcupine ' Expedition of 1869 at 1215 fathoms, and gives good figures of the 

 bristles. His specimens had respectively twenty-nine and thirty-five segments. 



Hansen found it in the collection made by the Swedish Expedition of 1876. 



Marenzeller (1877) includes this form also in the annelids of the Austrian North 

 Polar Expedition from a depth of 240 metres on mud. 



Verrill (1879) enters it in his list from Cape Cod to the St. Lawrence, where 

 Mr. Whiteaves dredged it in 1873. 



48 



