REPORT ON THE ANNELIDA. 
353 
muscles meet over the nerve-area, and are esj)ecially prominent above the latter in the 
interganglionic regions. The nerve-area is bounded laterally l)y the longitudinal ventral 
muscles, and has the circular coat, hypoderm, and cuticle externally. As in the genus 
Scoloplos, a single neural canal is visible quite at the upper border of the area in some 
preparations. A large blood-vessel occurs in the median line dorsally and ventrally, and 
the vascularity of the entire body-wall is great. 
This species appears to have a very wide distribution, stretching from the Norwegian 
shores into the Atlantic, and as far as the American shores. 
Aricia jActtycephala, n. sjj. (PI. XLIII. figs. 1-3 ; PI. XXIIa. figs. 16, 17). 
Habitat . — Found between tide-marks at Bermuda. 
The example consists of a fragment of the anterior region having a length of 38 mm., 
and a diameter of fully 4 mm. about a quarter of an inch Ijehind the snout. 
The snout (PI. XLIII. fig. 1) is flattened and spathulate, and therefore characteristic. 
A little pigment is present just within the anterior margin. The anterior feet, from 
the absence of papillse, appear somewhat bare. The first is small and bifid, each 
division having a few stout bristles. The second has a long dorsal appendage (cirrus) 
behind the bristle-tuft, and an elevated setigerous region with two processes posteriorly. 
There is only one of the latter at the third foot, and it soon becomes extended vertically 
into a somewhat crenate and not very prominent fold, provided with a papilla superiorly, 
the homologue of the pectinate rows of the ordinary form. The dorsal bristles are less 
conspicuous than iu the latter, and most are Ijroken. So far as can be observed, they 
consist of a stronger series of serrate yellow bristles with smooth basal regions, and 
numerous shorter and more slender forms of similar structure. At the tenth foot 
(PI. XLIII. fig. 2) the dorsal cirrus has a large basal swelling, . chiefly external. The 
stout bristles of the inferior series are arranged in four vertical rows on the flattened pad, 
the strongest being anterior. The general arrangement seems to be the following: — The 
two outer series (anterior and posterior) are continuous, with a small curve superiorly, each 
extending downward and expanding as it goes, the anterior, however, being the larger. The 
two middle rows also slightly expand inferiorly, the whole having a very regular as]3ect. 
The typical bristles of this row have long deeply set shafts, which somewhat increase in 
strength superiorly, and terminate in powerful, curved tips (PL XXIIa. fig. 16), which 
are easily distinguished by their brownish colour. The stoutest bristles of this series show 
slight traces of crenations on the convex edge, l)ut these ma}^ be absent, as in rhe figure ; 
while others (the more slender) have a terminal region more or less boldly serrate 
(PI. XXIIa. fig. 17). Their relationship with the ordinary spinous or serrate kinds 
is thus evident. Inferiorly, indeed, are several long serrate bristles. 
(ZOOL. CHALL. EXP. PART XXXIV. 1885.) 
LI 45 
