514 SCOLOPLOS ARMIGER. 



dorsal cirri and the papilla anteriorly, as well as variations in the length of the bristles, 

 specific separation of the northern and southern representatives does not seem to be 

 necessary or expedient. The following remarks will indicate the leading features relating 

 to the varieties : — 



The variety Mulleri (the Aricia Mulleri of De St. Joseph) is characterized by the 

 frequency of shorter bristles in the anterior feet — such bristles as are represented by 

 De St. Joseph in his figure 167, Plate XX. The structure thus figured and described, 

 however, might be explained by the occurrence of injury to the tapering bristles and the 

 rounding of the broken tips. As formerly observed, 1 they are modifications of the longer 

 series, not structures sui generis, and are apparently due to influence of habitat, e.g., 

 constant friction, and they vary much amongst themselves. De St. Joseph has the credit 

 of drawing special attention to them, and to the fact that in the first six segments of the 

 posterior region of the body the ventral division has two protuberances below it, with a 

 minute elevation near them, and a conical papilla on the body below. It is not explained 

 that a similar papilla occurs in the typical Scoloplos armiger from Greenland and the 

 northern waters. The two forms very closely resemble each other, the main features 

 which differentiate them being the somewhat longer rows of bristles in the southern form, 

 and the better developed fleshy ridge behind them with its flattened conical elevation in the 

 ventral division, and the two papillse just below it ; whilst the ventral row of bristles has 

 a variable number of short and somewhat truncate forms, which must not, however, be 

 regarded as specific. They are only modified forms of the ordinary tapering serrate kind 

 belonging to the division, and, as stated, are probably due to circumstances of habitat, and 

 are perhaps more abundantly present in those from the Channel Islands than in the more 

 northern examples. In this form a papilla appears in the middle of the fifth foot, and a 

 conspicuous one from the tenth to the thirteenth. At the seventeenth foot two papilla 

 occur, by the addition of one below the median, whilst the eighteenth has three, the 

 bristles being above (dorsal to) the upper. At the nineteenth foot the lateral ridge ends 

 dorsally in three conical processes, with a thick papilla beneath. In very fine examples 

 from Lochmaddy the papilla commences on the fifteenth, and continues to the twenty- 

 second foot. 



In the typical Scoloplos armiger from Greenland, the first fifteen anterior feet have 

 somewhat shorter (i.e., from above downward) ventral rows of bristles. The dorsal cirrus 

 is a well-marked conical process, which gradually increases in length posteriorly. The 

 fillet behind the ventral row of bristles forms a convex flap, highest in the middle, and 

 without any evident differentiation till the fifteenth foot, where a papilla projects from its 

 median convexity, one or two of the preceding feet showing a slight thickening at the 

 same part. The row of ventral bristles is shorter. Though the bristles are longer, the 

 row is still shorter at the sixteenth foot, and a papilla occurs on each side behind it. The 

 seventeenth foot has three papilla, whilst the eighteenth has the enlarged lateral fillet 

 with an isolated papilla below it, and this for three or more segments. A survey of a 

 series of specimens from Greenland shows considerable variations in the second division 

 of the body in the shape of the dorsal cirrus, which may be fusiform or lanceolate and 

 stalked, and in the length of the bifid ventral lobe. Yet these and other features are 



1 'Ann. Nat. Hist./ 7th ser., vol. xv, p. 45. 



