Gatty Marine Laboratory ^ St. Andrews. IHl 



cirrata, Sars, a northern form which extends from Shetland 

 to the S.W. of Ireland, and abroad to Greenland, Norway, 

 and Canada. The broad anterior edge of the short head is 

 smootlily rounded, or in some slightly bilobed. A somewhat 

 triangular ridge, with the base in front, passes ba-kward and 

 ends in a point posteriorly, from the apex of which a small 

 subulate tentacle springs. Two eyes are present, one on 

 each side of the ridge in front of the tentacle. A lamella 

 occurs at the base of the long tapering palpi. The body is 

 about 1-2 inches in length, and is little tapered in front, so 

 that it has a truncated aspect. It is rounded dorsally and 

 deeply grooved ventrally from end to end. The first foot bears 

 a branchia and a large hatchet-shaped lamella, with a conical 

 end superiorly and a somewhat straight margin inferiorly. 

 The ventral lamella is nearly as large, bluntly conical 

 superiorly, and curving to a sharp angle inferiorly. The 

 dorsal bristles are capillary, the long tuft being superior, the 

 shorter inferior. TJie branchiae continue of considerable 

 size to the 25th foot, the great dorsal lamella remaining 

 nearly as at the 10th foot and is almost reniform. The 

 ventral lamella is slipper-shaped, the broad end being upper- 

 most, and both are free. The winged hooks appear about 

 this (25th) foot, have a slight dilatation of the shaft above 

 the backward curve, then gradually diminish to the throat, 

 from which the main fang comes off at a little more than 

 a right angle, and a single spike occurs on the crown. Two 

 slender capillary bristles are below the hooks. The bristles 

 become very long and attenuate posteriorly, and wings are 

 not evident. Not a single British example is complete, and 

 few go beyond the 25th foot. 



The British species of the genus Spio have hitherto been 

 involved in considerable obscurity, for though three are 

 described by Dr. Johnston in the Catalogue of the British 

 JMuseum, it is by no means easy to identify them. Only two 

 are entered by Malmgren as occurring in northern waters, viz. 

 Spio filicornis , O. Fabr., and Spin seticornis^ O. Fabr,, both of 

 which were known to O. Fabricius, who founded the genus 

 for annelids with two long tentacles. Dr. Johnston in 1838 

 placed Nerine and Leucodore under the same head. QCrsted 

 separated the genera Nerine and Spio by the form of the 

 dorsal lamellae ; whilst Claparede showed that this distinc- 

 tion was artificial. Mesnil, again, thinks that Malmgren 

 complicated the question by I'eviviug the generic name 

 Scolecolepis and undid the advance made by Claparede, a view 

 which cannot now be held. Yet he affirms that Malmgren 



