ANNULATA.] LOWER PALAXOZOIC ARTICULATA. 129 
NEREITES CAMBRENSIS (Murch.) 
Ref.— Murchison, Sil. Syst. t. 27. f. 1. 
Sp. Ch.—Length unknown (upwards of two feet), usually seen in irregular obtusely angular contortions ; 
width three lines (or rather more, as the cirri have a gentle backward curve); width of the body half a 
line; cirri thick, gradually tapering, two lines long; feet forming thick, ovate, fleshy lobes, one and half 
lines long; distance between the cirri (equal to length of segments) one and half lines. 
The thick fleshy feet are not sufficiently distinct beneath the cirri in the above quoted figure, and 
these latter do not taper quite enough. A single indistinct specimen, a little wider than the above and 
having the feet slightly longer and more pointed, has occurred in the Scotch slates in the valley of the 
Tweed, in company with a multitude of the Orossopodia Scotica (M*Coy), and it may perhaps ultimately 
prove distinct; but as there are exactly the same number of feet and cirri in a given space, I have little 
hesitation in considering it as only a variety—if even so much, of the Llampeter species. 
Position and Locality —Not uncommon in the slates of Llampeter, and Var. a. very rare in the olive 
slate of Thorney Lee Quarry, on the Tweed (opposite Ashestiel). 
NEREITES Sepewicku (Murch.) 
Ref.—Murchison, Sil. Syst. t. 27. f. 2. 
Sp. Ch,—Usually disposed in long straggling trails, and short irregular rounded loops; length unknown 
(upwards of a foot); width of specimen slightly more than two lines (but the ends of the cirri curved, 
which diminishes the apparent width); width of body slightly more than half a line; length of the seg- 
ments (equal to the distance between the cirri) one line; length of cirri (supposing them straightened) one 
and half lines; feet narrow, slightly more than half the length of the cirri. 
I have been so fortunate as to detect the feet of this species in one part of the specimen in the 
Cambridge Collection; they are much smaller and more delicate than in the WV. Cambrensis. A semi- 
elliptical hollow space, rather difficult to account for, is frequently seen on each side between each pair 
of cirri; it strikes me it may be the trace of the sweeping action of the little bush-like, retractile packet 
of bristles, forming the locomotive organs of the allied recent worms. 
Position and Locality—Not uncommon in the olive slates of Llampeter. 
Genus. MYRIANITES (Mac Leay). 
Gen. Char.—Body longer and more slender than in Nereites; cirri of the feet short (scarcely as long 
as a segment of the body, or the distance between one cirrus and the next); feet indistinct. 
Myrianites Macreayti (Murch.) 
Ref—Murchison, Sil. Syst. t. 27. f. 3. 
Sp. Ch.—Upwards of a foot long, usually coiled in long curved transverse folds, about one-fourth of 
an inch between the parts, which are very frequently approximately parallel; width of the animal throughout 
slightly more than one line, of which the body occupies nearly one half (being half a line wide), the cirri 
of the feet forming the remainder; the space between the cirri on one side slightly exceeds their length, 
being equal to the width of the body (indicating segments as broad as long). 
The above quoted figure represents the worm slightly too wide where the cirri are marked. 
Position and Locality—Not uncommon in the olive slates of Llampeter. 
