MbLLtJSCbiDA. 
399 
sufficiently distinct. Ascidia conchitega of Miiller) referred by Foster to the 
restricted genus Ascidiay proves to be a Molgula j it had not been found pre- 
viously on the eastern coast. 
The remarkable Ascidian ChevreuUus callensis (H. L. Du- 
thiers, 1 . c.) has, as Mr. Alder has mentioned (Ann. of Nat. 
Hist. Feb. 1866, p. 152), been previously described by Stimp- 
son (Proc. Acad. Nat. Sb. Phil. 1856, p. 377), under the 
name of Schizascusj with the following character Tunica 
exterior fissa ; parte posteriore complanata, cavum alterius tam- 
quam operculo claudente et siphones retractoS celante • aperturae 
Sexaiigulatse.^^ It is also referred to by Dr. Macdonald under the 
provisional name of Peroide$ in Trans. Roy. Soc. Edinb. vol. xxiii. 
1864, p. 179. This paper waS read in 1861. Dr. Macdonald 
aftertvards gave a detailed accotint of this Strange form under 
the name of Per d {vide Jodrii. Linn. Soc. vi. 1862, Zool. p. 78, 
figs. 1-4). 
The following species are already known (Schizascusj Stimp- 
sori, l856=rjPera, Macdonald, lS62—PeroideSj Macdotiald, 
lS64=Che:vreuliuSj L.-DuthierS, 1865) .* — 
1 . S. pelluciduhj StimpSon, China j 2. S. papillosum , Stimpson, 
China; 3. /Sf. huxleyij Macdonald, Bellona Reefs; 4. S, caU 
lehsisj Lacaze-Duthiers, Calle. 
In S. papillosUs the ocelli at the angles of the aperture are of 
a salmon-colour. 
Dr. Macdonald^s description and figures, though appearing in 
a well-known journal, have been strangely overlooked. Although 
Dr. Lacaze-Dtithiers^s memoir does riot describe a riew gerius, it 
gives to us the first detailed account of the anatoriiy of this Very 
interesting form, tvhich he believes to strengthen the connexion 
that exists between the Ascidia and the Brachiopodttj as in it the 
mantle divides into two portions, the one superior, the bther 
inferior, just as is met with among the BracMopoda, 
POLYZOA. 
The researches of Mr. Smitt (/. C.) appear to confirm the views 
expressed by him (in yearly Report of the Xlpsala University for 
1863) as to the significance of the fat- corpuscles (FettkrOppar), 
while they prove at the sarile tiirie that the modes of propagation 
are very numetoUS among the Poly (Bryo)zoa. Their living in 
coloriiCS and consequent polymorphism is necessarily intiinately 
connected with their mode of development ; arid in spite of the 
dissimilarity that will be met with in the multiplication and de- 
velopment of different Species, a pervading agreement in the sig- 
nificance arid use bf the Fettkroppai* will bc found ; the follow- 
ing examples will show this \ — 
