104 Dr Grants Ohservatimis on the , 



In treating of the different species of Rhus which were sup- 

 posed to resemble the varnish tree, Mr Ellis mentions " that the 

 Rhus Shiense, when first it began to extend its leaves in the small 

 stove, had so remarkably a disagreeable smell, that he frequently 

 complained of getting the headache, and a sickness of his sto- 

 mach, by remaining too long near it ; and after it was removed 

 into the great stove, where, notwithstanding that building was 

 very spacious, and near twenty feet high, yet, as it grew most 

 luxuriantly, we could not without pain continue long near it." 



Art. XVII. — Observations on the Generation of the Lobii- 

 laria digitata^ Lam. (Alcyonium lobatum, Pall.^ By R. 

 E. Grant, M. D., F. R. S. E., F. L. S., Professor of Zoo- 

 logy in the University of London. Communicated by the 

 Author. 



In various observations and experiments on the structure and 

 economy of Zoophytes found inhabiting the Frith of Forth, I 

 have already shown that in many silicious, calcareous, and 

 horni/ species, theminute reproductive gemmules by which these 

 animals propagate, are highly organized portions of the gela- 

 tinous substance of the parent, which possess the power of 

 swimming freely to and fro, for a considerable time after their 

 separation, by the rapid vibration of very small ciliae covering 

 their surface. Although I had not an opportunity of observ- 

 ing this singular phenomenon in any zoophyte which discharges 

 its ova through the bodies of polypi, I was induced from analogy 

 to believe that the motions observed by Cavolini in the ova of the 

 Caryophyllia and Gorgonia, which are discharged through po- 

 lypi, were produced by similar organs, and that these organs in 

 the same situation are probably of much more general occurrence 

 in this class of animals than has yet been observed. During 

 the month of October I procured some specimens of the white 

 variety of Lobidaria digitata from the Frith of Forth, with 

 their ova in a state of maturity, which afforded me the means 

 of observing the process of generation, not only in a species 

 whose ova pass through polypi of a very complicated struc- 

 ture, but also in a zoophyte with Sijleshy and contractile axis, 



