EEPOET ON THE ANNELIDA. 
149 
from before backward. The general outline of these scales is somewhat triangular, with 
a deep groove bordered by an elevation at each side on the anterior border. Almost 
the entire margin is surrounded by cilia. In the arrangement of the sandy, and 
other grains on the dorsum of each, it is observed that a somewhat regular gradation 
occurs from before backward, the finer particles occurring anteriorly and the coarse 
posteriorly. They are also less affected by the ferruginous hue than the succeeding. 
The other scales generally are coated externally by a ferruginous deposit, over which 
the sand-grains are attached. The anterior margin alone is free from the latter, and 
is also smooth ; while the rest of the margin is surrounded by a dense series of cilia, 
which are longest on the inferior border, where they likewise show a tufted arrangement 
on slight elevations, the intermediate spaces having short papillae (PI. XXIV. fig. 6), 
as Grube indicates in Psammolyce umhonifera} The surface of the scale appears to 
be covered with distinct papillae, almost all, however, being shrouded in sand-grains 
and ochreous mud. The scales are proportionally larger than in the previous form, and 
they readily fall off. 
Each foot has a well-marked branchial process superiorly, and long slender cilia 
(papillae) along the external and inferior borders. These processes are longer than in 
Psammolyce sombreriana. The ventral cirrus extends beyond the base of the bristles. 
The superior division of the foot bears a dense tuft of curved serrated bristles, 
generally coated inferiorly with the ochreous deposit ; and internal to their base is a 
well-marked lamellar collar. 
The ventral lobe has a series of brownish bristles with an elongated, bifid, terminal 
process articulated distally in the usual manner (PI. XIIIa. fig. 18, an intermediate 
form). On the whole, the terminal appendages are longer than in the last species. 
The leading differences, therefore, between this form and Psammolyce sombreriana 
are — the more prominent head, the presence and position of the eyes, the large size and 
structure of the basal segment of the tentacles, the more evidently spinous condition of 
the dorsal bristles, the greater comparative length and the structure of the tips of the 
ventral bristles, the more elongated papillae on the feet, the ferruginous deposit, and 
the substitution of sand-grains for Foraminifera on the scales: 
The differences just noted in external characters are fully borne out by an examina- 
tion of the structure of the body-wall. The surface shows a dense extraneous deposit, 
which often envelops the papillae in a continuous mass, and the cuticle ventrally is 
proportionally thicker. The nerve- area, while following the same type, is deeper and 
narrower, and the ventral longitudinal muscles show only a gentle curvature. The 
dorsal longitudinal muscles are also proportionally thicker inferiorly. In ordinary 
sections there is a deep median furrow between the cords superiorly, a feature 
intensified by the parting of the oblique and vertical muscles in the same region. 
1 Anneliclenausbeute von S.M.S. “Gazelle,” op. cit, p. 521. 
