SCOLOPLOS APMIGER. 513 



of which are smooth (Plate LXXXVI, figs. 1 and 1 '),but the tapering tips are peculiarly 

 spiked, and they terminate in smooth hair-like points. Four somewhat short spines 

 support the bristles. The ventral division has two short conical papillae, one of which is 

 below the bristle-tuft, and is probably the representative of the ventral cirrus, whilst the 

 other is a little below the middle of the bristles, which form a dense and deep row, shorter 

 than the dorsal but of the same type. At the ninth foot, however, the papillae are 

 smaller, and the inferior division has numerous short strong bristles with somewhat blunt 

 tips, which are strongly curved and serrated on the convex side. They are modified 

 forms of the longer series, and correspond with the stronger series in Aricia. The same 

 is seen in the tenth foot (Plate LXXXVII, fig. 4). 



The branchiae commence in the form of small papillae from the fifteenth to the 

 seventeenth foot, attain considerable size on the twentieth foot, rather increase in pro- 

 portional length in their progress backward, and almost reach the tip of the tail. 



Below the foot from the eighteenth bristled segment to about the thirtieth (fewer in 

 some) a papilla occurs on the side of the body. It varies in prominence, it may be in 

 some cases from preparation, and is very well marked in Zetlandic examples from 

 Symbister. This feature is variable. Thus, in an example from Lochmaddy the papilla 

 appears on the seventeenth bristled segment. At the twenty-fourth and twenty-fifth it 

 has become scale-like, and adheres to the front edge of the ridge from the foot. 



The eighteenth bristled foot shows considerable alteration. Externally, that is, 

 ventrally, is a small papilla, then a bifid process with the bristles. The dorsal division 

 consists of a longer conical papilla with a fan-shaped tuft of bristles. The ridge of the 

 segment below the feet also becomes more prominent in this region. 



At the twentieth foot (Plate LXXXVII, fig. 4 a) the ventral division presents a 

 somewhat lanceolate outline, and the bristles are slender and almost smooth. The dorsal 

 papilla is constricted at the base, then dilated, and slightly tapered to the tip. It bears a 

 fan-shaped tuft of long bristles, with smooth shafts and tapering serrated tips. It 

 adjoins the branchia. 



The thirtieth foot (Plate LXXXVII, fig. 4 b) has ventrally a bifid setigerous region, 

 with a rounded enlargement at the base ventrally. The bristles are few, long, slender, 

 and very finely serrated — quite different in aspect from the dorsal. The dorsal lobe is 

 constricted at the base, with a lanceolate terminal region tapering to a point. The 

 bristles have smooth shafts and boldly serrated tips. The branchia is a richly ciliated, 

 flattened lanceolate organ, with central vessels which apparently have pinnate lateral 

 branches. 



Cunningham and Ramage figure l a bifid bristle as occurring in this species, where, it 

 is not stated. A mistake may have happened, especially as the inner edge of the fork is 

 smooth. 



On the whole, while there are certain differences in the proportional length of the 



1 'Trans. R. Soc. Edin./ vol. xxxiii, pi. xxxviii, fig. 7 e. This recalls the case of a foreign 

 observer, who showed this kind of bristle in another species in a proof of the plate. The absence of 

 these spikes was pointed out, the author asserting that the limbs of the fork were smooth. When the 

 paper and its plates subsequently appeared the spikes had taken their proper places. 



122 



