REPOET ON THE TTJNICATA. 
295 
Leftodinum jeffreysi} n. sp. (PI. XL. figs. 6-9). 
The Colony is a flattened expansion of irregular form. It is incrusting, and is 
attached by the whole of the lower surface. The upper surface is somewhat uneven but 
smooth. The colour is a duU creamy white. 
The length is 3*5 cm., the breadth is about 2 cm., and the thickness is from 
1 to 2 mm. 
The Ascidiozooids are fairly numerous, but of small size. Their anterior ends are 
visible on the upper surface as small inconspicuous dots. They seem to be scattered 
evenly over the colony. No common cloacal apertures are visible. 
The Test is hard and brittle. It is of a white colour and quite opaque. The upper 
surface contains great numbers of calcareous spicules, while the lower part is crowded 
with large bladder cells, and has no spicules. Small test cells are scattered all through 
the matrix, but they are not numerous. The spicules are stellate, but their rays are 
short and vdde. They are of a slightly yellow colour. 
The Mantle is thin and not strongly muscular. The branchial sphincter is strong. 
The Branchial Sac is small and feebly developed. 
The Endostyle is conspicuous. 
Loccdity. — Tangier Bay, Morocco, August 5, 1870 ; depth, 35 fathoms. 
One colony of this species was obtained during the Mediterranean cruise of the 
“ Porcupine,” in the summer of 1870, in Tangier Bay, from a depth of 35 fathoms. It 
is a small irregularly shaped expansion of a dirty cream colour, and having various 
fragments of Polyzoa and sand grains attached to its lower surface and edges (PI. XL. 
fig. 6). The Ascidiozooids are small and inconspicuous. They occupy only the upper 
half or so of the thickness of the colony (PI. XL. fig. 7), and they are not arranged in 
definite systems. 
Vertical sections through the colony show that the test may be divided into two zones 
(see PI. XL. fig. 7) ; an upper containing the bodies of the Ascidiozooids, and densely 
crowded with calcareous spicules, and a lower into which the Ascidiozooids do not 
extend, and which contains no spicules, but is occupied by a large number of bladder 
cells (PL XL. figs. 7, 8). The bladder cells are usually spherical, but in some places they 
become polygonal from mutual pressure.. They do not extend quite to the lower surface 
of the colony (PI. XL. fig. 8, l.s.). 
The spicules are of moderate size and usually of stellate form, but the rays are very' 
short and wide and the central part is large, so that the spicule as a whole has often 
the appearance of a sphere covered with small pointed excrescences. The spicule 
1 This species and the two following ones are named in honour of the three distinguished naturalists who conducted 
the scientific investigations during the cruises of H.M.SS. “ Lightning ” and “ Porcupine ” in the summers of 1868, 1869, 
and 1870 — the late Dr. Gwyn Jeffreys, the late Dr. W. B. Carpenter, and the late Sir WyviUe Thomson. 
