SM 
Z. ASCIDIOIDA 
Plumatella 
Trembley, and his Tubularia gelatinosa, in a living state, and he as- 
serts that the latter— -a Plumatella — differs from the former — an Al- 
cyonella — not solely in habit,* but in having fewer, shorter, and more 
recurved tentacula. “ Interaneis quoque” he adds, “ a prsecedenti 
differt et distinctissima est hcec species, quae interdum in iisdem cum 
prsecedenti (semper rariore, adeoque, ut videtur, minus prolifica) re- 
peritur aquis.” Muller’s description of Plumatella repens certainly 
affords nothing in opposition to Raspail’s theory, but on the contrary 
may be deemed favourable to it, since he tells us that it is intermedi- 
ate between the very species which Pallas considered so widely diffe- 
rent, possessing many of the characters of both, and differing princi- 
pally in the appearance of the polypidom. Lamarck perceived the 
affinity of the genera, which he nevertheless kept separate, resting 
the distinction on the massive and ramous forms of the polypidoms. 
Baer, apparently speaking from personal examination of the produc- 
tions in question, has expressed his conviction of the perfect distinctness 
of Alcyonella and Plumatella, and this subsequent to his knowledge of 
Raspail’s Memoir : and Milne- Edwards has still more recently shown 
that this essay had at least not conveyed perfect conviction to his 
mind, otherwise he would scarce have expressed himself in this man- 
ner : “ II nous parait en effet probable que ces Polypes, observes a 
des periodes diverses de leur developpement, ont ete pris pour des 
animaux differens et decrits sous des noms parti culiers. Mais il se- 
rait possible aussi que les formes transitoires de l’Alcyonelle decrites 
par M. Raspail se rencontrassent d’une maniere permanente chez 
d’autres Polypes, et par consequent, on ne peut encore rayer des ca- 
talogues zoologiques la longe suite d’especes mentionnees ci-dessus.” 
Lam. Anim. s. Vert. 2de edit. ii. 116. — Under these circumstances 1 
have deemed it the best course to keep the genera separate, as least 
likely to perplex the student. 
Of the P. Sultana little is known. 1 have seen a living specimen 
in the possession of Sir John G. Dalyell, but had no opportunity of 
making an examination of it. Naturalists wait with some impatience 
the publication of a work from this ingenious observer, on which, it 
is understood, he has been long engaged, and which will disappoint ex- 
pectation if it does not disclose many novel facts, and illustrate many 
present obscurities, and give additional respect and permanence to 
his name and reputation as a naturalist. 
* “ Habit is a general agreement in growth and appearance.” f.innaus. 
