SOME OBSERVATIONS ON ACINETARIA. 637 
die langathmige Hrérterung unnéthig geworden. Hoffent- 
lich wird dieses bald nachgeholt.” 
Sand, in his ‘Htude Monographique sur le Groupe des 
Infusoires Tentaculiféres, published in 1901, returns to Clapa- 
réde and Lachmann’s original view. On p. 76 he states :— 
“Nous croyons tout simplement qu'il n’y a pas plus de 
différence entre un Proboscidien et un Lagéniforme qu’entre 
un Dendrocometes dont les bras sont étalés et un Dendro- 
cometes qui les a retractés. Souvent il est vrai la forme 
exterieure des deux variétés d’Ophryodendron n’est pas 
identique mais ce caractére n’est pas constant: nous avons 
vu des Lagéniformes identiques a des Proboscidiens et des 
Proboscidiens analogues a des Lagéniformes.”’ 
He did not succeed in watching the ciliate embryos or the 
animal feeding, but he states (p. 35): ‘‘ D’apres nos observa- 
tions, les corpuscules naviculaires d’Ophryodendron belgicum 
sont identiques, comme dimensions et comme aspect aux 
granulations de l’ectosare des Hydroides sur lesquels les 
Ophryodendron sont fixés.” 
To his further observations, especially those dealing with 
the structure of the vermiform individual, with most of 
which I can find no point of agreement, it will be necessary 
to return in the special part. 
3. MateriaAts AND MeEtHops. 
It will now be necessary to give my own observations on 
Ophryodendron, most of which were, to a large extent, con- 
trolled by work on the living animal. Most of the work 
was done on Ophryodendron abietinum (Claparéde and 
Lachmann) which was found growing on Clytia during the 
months of July and August at Plymouth, and on Obelia 
during the months of October, November, and December at 
Millport in a particularly mild winter. 
I should like to thank the staff at both these laboratories 
for the readiness with which they assisted me in obtaiming 
material, and for the facilities they gave me for working it 
