of Edinburgh, Session 1865-66. 605 
the region, and a central one, the whole having the shape of the 
inverted G-reek letter w, and resembling a crown. The visceral 
region dwindled to a streak before reaching the radiciform pro- 
longations at the base. 
The simple Ascidians were represented by A. intestinalis, A. 
canina, A. mentula, A. scahra, and A. aspersa. Accompanying the 
latter were one or two hard, reddish species, that apparently could 
be classed with neither. From the deep water of the Minch came 
several Ascidians, slightly adhering to each other by the extraordi- 
nary debris of shells, mud, and corallines, that surrounded them, 
yet otherwise solitary and distinct, like Molgula oculata. Their 
orifices were situated on separate fleshy papillse, the anal having 
eight streaks of crimson, with intermediate pale lines ; the 
branchial somewhat larger and more prominent, but similarly 
tinted. Molgula tuhulosa was occasionally met with on muddy 
ground (six fathoms) in Lochmaddy. The papillm were greyish- 
brown ; and when placed in spirit, it speedily cast off its coating 
of mud and minute shell fragments. 
Cynthia rustica and G. grossularia are frequent between tide- 
marks, but not at the extreme verge, for that seems rather occupied 
by sponges and zoophytes. If a stone having its under surface 
covered with the former is turned over, death and discoloration of 
the Ascidians soon take place, although they remain in the same spot 
as regards the tide. G. ampulla (?) was dredged in twelve fathoms 
on hard ground ; it had a tunic covered with sandy hairs, with a 
clear space on which the two long pinkish apertures were situated. 
A small specimen allied to C. tesselata was also dredged. On the 
test of a large A. mentula from the Minch were several examples 
of Cynthia Uistim, new sp. (fig. 3). The largest were about a 
a quarter of an inch in diameter, globose, and hisped with branched 
bristles springing from papillaB on a tough greenish tunic. It differs 
from the Ascidia echinata of Professor Forbes in having four divi- 
sions to its branchial orifice, in having no regularity in the arrange- 
ment of the bristles, and in their want of radiation. 
The countless multitudes of Sal pa spinosa and S. runcinata, in 
both solitary and aggregate forms, is also a noteworthy fact. 
One of the most striking features in the distribution of the 
mollusca (proper) of the island is the abundance of wood- borers. 
