EEPORT ON THE ANNELIDA. 
503 
Dasychone nigro-maculata, (Baird) (PL LIII. fig. 5 ; PL XXXIa. figs. 4-6 ; 
PL XXXIXa. fig. 6). 
Sabella nigro-maculata, Baird, Journ. Linn. Soc. Lond., viii. p. 159, pi. v. figs. 5, 6. 
Habitat . — Found between tide-marks, St. Thomas, West Indies, March 23, 1873. 
The body measures about 37 mm. in length, and the branchije extend to another 
11 mm. The diameter at the widest part is 6 mm. 
The body is somewhat rounded dorsally and flattened ventrally, and rather abruptly 
tapered toward the tail, on which the anus is distinctly dorsal in position. The ventral 
median line passes forward to the front of the abdominal region, cutting the second scute 
obliquely to the right of the middle line, and the right corner off the first scute, in its 
passage to the groove between the thoracic and abdominal regions to turn upward on 
the dorsal., surface. It forms a pale groove on the latter surface, at first directed 
obliquely forward and inward, and is lost anteriorly in the median cephalic groove. A 
faint dorsal line exists all along the body, an indication probably of the raphe, but it 
forms no distinct groove. 
The cephalic collar has its dorsal edges wide apart, and no accessory dorsal lamellae 
exist as in the previous species. It continues without break to the ventral furrow, and 
terminates in a large auricular process on each side of the fissure. 
The body and collar are blotched and speckled with dark brownish or purplish-brown 
spots. A well-marked brown spot occurs between the setigerous process and the 
uncinigerous row, both in the thoracic and abdominal regions ; and there is also a less 
distinct speck at the inner termination of the hook-rows in the latter region. The 
darker pigment in the thoracic region, however, may obscure the s^Deck. 
The somewhat short branchiae number on each side from forty-two to forty-three. 
In the preparations their colour is brownish, mottled here and there with pale patches. 
Externally a series of rather short appendages occur in pairs (PL XXXIXa. fig. 6), the 
first appearing in the sulcus at the base between the radioles, which are numerous and 
slender. The pinnae become shorter toward the tip, but none of the branchiae are so 
perfect as to show whether any bare filament does or does not exist at the extremity. All 
that can be said is that such is probable. The radioles present a segmented appearance,, 
a depression with an encircling line occurring at regular intervals, a little beyond each 
pair of external processes. The segments are comparatively short. A little beyond the 
distal edge of the segment-junction are a pair of lateral (ocular) pigment-spots. The 
axial tissue of the radioles is fairly developed, so that they are firm. 
The thoracic region consists of eight segments. The dorsal bristles (PL XXXIa. fig. 4) 
are somewhat similar to those of the previous species, but the tips are decidedly more 
spinulose both along the edges of the wings and on the dorsum (or opposite side). The 
