404 POLYZOA HYPPOCREPIA. 



which I have witnessed the remains of the food swallowed but a 

 short time before forcibly ejected." Fleming. 



As I have already stated, Raspail considers the Plumatellse to be 

 merely states of the Alcyonella, an opinion which future inquiries 

 may shew to be true, but at present there are some difficulties in the 

 way of its adoption. 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 production in question, 

 has expressed his conviction of the perfect distinctness of Alcyonella 

 and Plumatella, and this subsequently 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, other- 

 wise he would scarce have expressed himself in this manner : " II 

 nous parait en effet probable que ces Polypes, observes a des pe- 

 riodes diverses de leur developpement, ont ete pris pour des ani- 

 maux differens et de"crits sous des noms particuliers. Mais il serait 

 possible aussi que les formes transitoires de 1'Alcyonelle decrites par 

 M. Kaspail se rencontrassent d'une maniere permanente chez d'autres 

 Polypes, et par consequent, on ne peut encore rayer des catalogues 

 zoologiques la longue suite d'especes mentionnees ci-dessus." Lam. 

 Anim. s. Vert. 2de edit. ii. 116. Under these circumstances I have 

 deemed it the best course to keep the genera separate, as least likely 

 to perplex the student; although aware that the observations of 

 Mr. Hassall are much in favour of Raspail's view. See Ann. and 

 Mag. N. Hist, x, 153. 



2. PL. EMARGINATA, " polypidom cylindrical, closely ad- 

 herent in the greater part of its extent, but sending off several 

 short free branches, about half an inch in length ; margins of 

 apertures with a deep notch, ichich is filled up by a transparent 

 membrane.' 1 '' Allman. 



Plumatella emarginata, Allman in Ann. and Mag. N. Hist. xiii. 331. 



Hob. Fresh water. Bandon, Dublin, G. J. Allman. 



3. PL. FRUCTICOSA, ''polypidom shrubby, adherent in but a 

 part of its extent, suddenly dilated towards the aper- 



; margins of apertures entire.' 1 '' Allman. 



Plumatella fruticosa, Allman in Ann, and Mag. N. Hist, xiii, 331. 



Hah. Fresh waters. Bandon, Glandore, Dublin, G. J. Allman. 



