REPORT ON THE TUNICATA. 
177 
areolated or thickened irregularly so as to form a series of knobs or very short ceeca ; but 
it differs from all of these groups in having the branchial aperture surrounded by eight 
lobes in place of six. This last feature it possesses in common with Giard’s two genera 
Circinalium and Fragariitm, from both of which it is separated by the structure of the 
stomach- wall. Amongst those genera with areolated stomachs (see Table, p. 152) 
Morchellioides is most nearly related to Morchellium on account of the compound systems 
and the sessile post-abdomen ; and amongst genera with more than six lobes round the 
branchial aperture it is most nearly related to Fragarium, again, on account of the 
compound systems. Consequently the nearest allies of the present genus appear to 
be : — on the one side Morchellium, with only six lobes round the branchial aperture, and 
on the other Fragarium, with a folded or ridged stomach-wall. 
The genus Paixiscidia was founded by Milne-Edwards for the reception of forms allied 
to Amaroucium, but having eight-lobed branchial apertures, and Alder very properly 
referred to that genus the species described by Fleming and Forbes under the name of 
Sidnyum turbinatum along with a species of his own, all of them being characterised by 
eight-lobed branchial apertures. Parascidia must be very closely related to Fragarium, 
Circinalium, and Morchellioides, but unfortunately none of the published accounts of it 
are sufficiently detailed to show whether or not it is distinct from all of them. 
Morchellioides can be separated from Fragarium and Circinalium, but may possibly be 
the same as Parascidia. 
Further points in the structure of the present genus will be found noted under the 
description of the single species which follows. 
Morchellioides affinis, n. sp. (PI. XXIV. figs. 16-20). 
Th.e Colony is an irregularly globular or dome-shaped mass attached by a wide base 
and slightly compressed laterally. The widest part is a little way above the base,- and 
the top is rounded. The surface is even, but finely roughened all over. The colour 
is a warm yellowish -grey. 
The length is 4 cm., the greatest breadth is 3 cm., and the thickness is about 2 '5 cm. 
The Ascidiozooids are numerous and fairly large. They are very distinctly visible 
all over the colony, and are not arranged in regular systems. They are usually about 
7 mm. in length and 1 mm. in breadth, and the body is not distinctly divided into 
regions externally. The widest part of the body is in the branchial region. Vascular 
appendages are given off from the posterior end of the body. 
The Test is thick and moderately firm. It is of a light grey colour and is semi- 
transparent. The test cells are small but very numerous. There are no bladder cells 
and no pigment corpuscles, but a few rather narrow vessels are present ; they end in 
slightly dilated knobs. 
(ZOOL. CHALL. EXP. PART XXXVIII.— 1885.) 
Pp 23 
