4' 



It seems to me further that it would be undesirable to attempt to replace Flustrella 

 Gray by either Elzerina Lamouroux, 1816, or Verrucularia v. Suhr, 1834. There is some 

 doubt as to the species which Lamouroux intended ; while it can hardly be considered proved 

 that the branching- Southern species which I have included under Elzerina really belong to 

 the same genus as the European species. Even if it be admitted that Elzerina should be 

 placed in the Flustrellidae, it may still be considered that the zoarial form justifies its separation 

 from Flustrella. To refer the branching species to the same genus as the encrusting European 

 species may be to suggest a wrong idea with regard to the geographical range of Flustrella. 

 F. kispida has a remarkable bivalved larval form which, so far as is known, is almost peculiar 

 to that species. In the absence of information with regard to the larvae of the Southern species, 

 it would be unsafe to assume that they are really congeneric with F. kispida. It thus appears 

 to me preferable to retain Gray's name for F. kispida- ; and in view of the fact that this has 

 been generally accepted for so many years I venture to think that it would be better not to 

 disturb it even if it were admitted that it is synonymous with Elzerina and Verrucularia. 

 Elzerina may perhaps be retained for the erect, branching Oriental and Southern species. 



PALUDICELLEA , STOLONIFERA and VESICULARINA. 



Before discussing the systematic arrangement of the Ctenostomata included below under 

 these groups, the method adopted for mounting preparations may be indicated. 



In spite of the delicate nature of the body-wall in the genera here considered ; — which 

 might have been expected to render them easily permeable to reagents ; — it is well known 

 that the microscopical preparation of this group of Polyzoa is attended with special difficulties. 

 It is most desirable to find some method of mounting a type-specimen in Canada balsam, 

 and thus to give it as permanent a character as possible; but, in spite of many experiments 

 which I have made, I have been unable to discover any process by which the transference 

 into that substance can be effected satisfactorily. There is no difficulty in obtaining material 

 which is well preserved in either spirit or formalin. But on using oil of cloves, or creasote, 

 a shrivelling of the body-wall almost invariably takes place ; suggesting that the cuticle is 

 specially impermeable to anything in the nature of an oil. This property increases with age, 

 so that while the very young zooecia can sometimes be transferred to the oil without any 

 undue amount of shrinkage, the older zooecia and the older parts of the "stolon" commonly 

 collapse when treated with a reagent of this nature. In some cases, moderately successful 

 results can be obtained by dispensing with the use of an oil and transferring the preparation 

 directly from absolute alcohol to Canada balsam dissolved in absolute alcohol, as recommended 

 in my paper on the Morphology of the Cheilostomata l ). But even when this procedure is 

 foliowed the results are often very disappointing. In a few cases I have had some success by 



ij Harmer, S. F., 1902, Quart. J. Mier. Sci., XI.VI, p. 264. 



SIBOGA-EXPEH1T1E XXVIIItf. 



