Neiu J^ictoricioi Haloragis and Genus Pluchea. 139 



moreover, louo- ciliated. Some deo;ree of dicecism is 

 however characteristic also of P. tetranthera and P. 

 baccharoides, while pappus-bristlets in a single or in more 

 than one row, and with various extent of denticulation or 

 even ciliation, occur together in some other genera of 

 Compositse, for instance, in Senecio. The remarkable 

 narrowness of the stigmata in our species, as well as their 

 structure, are quite in accord with Pluchea, so also the 

 sagittate base of the anthers, although the latter is reduced 

 to extreme minuteness. This Pluchea, however, connects the 

 genus evidently with the exclusively American Baccharis, 

 and a section in Pluchea, as Natho-Baccharis might be 

 established for it. The involucral bracts of P. conocephala 

 arise all closely together from the exceedingly small 

 receptacle ; the corollas when dry are dull and dark-coloured 

 towards the summit, but may be purplish when fresh ; 

 those of the staminate flowers being shorter than those of 

 tlie others ; the filaments are comparatively short ; the 

 terminal plate of the anthers is almost semi-lanceolar ; the 

 stigmas of the flowers with rudimentary anthers are fully 

 exserted, those of the other kind of flower much enclosed 

 and thicker than in many other species ; the achenes are 

 comparatively long. The pappus is almost that of Pterigeron. 

 Additionally it may also here be noted, that Eurybia rudis 

 is transferable to Erigeron, in which genus it should form 

 a distinct section. 



Art. XIII. — Notes froTn the Biological Laboratory, 

 Ormoncl College. 



I. Observations on the Movements of Detached Gills, Mantle- 

 lobes, Labial Palps, and, Foot in Bivalve Mollusks. 



By D. McAlpine, Esq. 



[Eead October 13, 1887.] 



The present paper will only deal with the results of these 

 observations, without giving any detailed description. 



It has long been known that the gills, for instance, of 

 bivalve mollusks, exhibit ciliary motion in a very marked 



