PHOLOE MINUTA. 441 



on the distal pieces of the ventral bristles. In specimens from the St. Lawrence, 

 Canada, the bristles agreed more with the arctic forms, and one had a translucent 

 granular deposit on them. The spikes at the end of the shaft were indistinct, but this 

 also occasionally occurs in the British examples. 



In considering the two varieties (inornata and eximia) it is clear that no reliable 

 distinction can be drawn from the structure of the bristles, and this is probably more 

 important than the condition of the cilia on the scales. It is true the end of the shaft is 

 most spinous — that is, has a longer series of spines from above downwards — in var. 

 inornata, and that the dorsal bristles are more distinctly spinous, and the ventral warts 

 or papillae more conspicuous, but the characters are not new, and only vary in degree, 

 and are probably due to the surroundings, with which we are, perhaps, not fully 

 acquainted. The steps from var. eximia to var. inornata, and thence to the typical 

 minuta from the arctic seas, are easy, both as regards scales and bristles. 



After a careful consideration of all the facts it has been thought best to unite the 

 varieties into a single species. 



Reproduction. — Male elements as minute granules occurred in August at Lochmaddy. 

 At St. Andrews ripe males are common at the end of June, so that the breeding period 

 would seem to be in July. The spermatozoa have globular heads and long tails, and 

 resemble those of Lepidonotns squamatus, a species with the same breeding period. The 

 examples of P. minuta from Greenland present ova in July. 



Development. — Trochospheres, apparently of this species, occur near the bottom on 

 September 12th, presenting only four crenations posteriorly to indicate the seg- 

 ments. 



On September 10th the youngest stage has a bluntly conical prostomial region, 

 which appears to occupy about half the bulk of the animal. Two small black specks 

 are situated posteriorly. At each side are the short tentacular cirri. Four bristled feet 

 follow, with stout bristles having the typical structure. Two spines occur on the dilated 

 end of the shaft, the most prominent being inferior. Besides these stout bristles each 

 foot has one or two much more slender forms, with a long, tapering, diaphanous terminal 

 piece, evidently a larval ventral bristle. The dorsal bristles have the adult structure, 

 being slender, tapering, hair-like, serrated bristles. The dorsal cirrus is much enlarged 

 at the base, but with a slightly tapered tip. 



What appear to be three pairs of scales have the aspect of globular organs on a 

 pedicle, each with several large truncate papillas projecting from the edge. These 

 papilla are out of all proportion to the condition in the adult. Viewed from below the 

 ventral cirrus shows a basal swollen region (ceratophore) and a two-jointed cirrus, while 

 some distance inwards is a globular papilla. The body, which is marked by transverse 

 lines at this stage, terminates posteriorly in a broad pygidium. 



In the next stage (which, however, is of the same date— September 10th, 1888) the 

 snout is truncated, and the caudal process has a dimple in the middle. Then the head 

 becomes denned as an oblong mass, rounded in front and flanked by the two tentacular 

 cirri, which now are directed forward on each side. There are still only four bristled 

 feet. The cilia on the scales are longer, and two short, broad, caudal cirri have 

 appeared under the pygidium. 



