Miscellaneous. 307 



axis of this singular production belongs to the class of Spongidce, and 

 the polypi which we have observed in a dried state on different parts of 

 the axis appear to be parasites belonging to the order oiZoantharia." 



I have not seen M. Valenciennes' s paper in which this theory is 

 propounded, or the ground on which it is supported, but I have seen 

 the specimen in the Paris Museum on which the observations I sup- 

 pose have been made. It is a very imperfect one, and I suspect that 

 its imperfect condition has been the cause of this theory. 



Besides the Paris specimen, we have in the British Museum two ; I 

 have in my own collection one ; and in the Dutch collections I have 

 seen five or six specimens of this coral. They have all the same form 

 and structure, and are all more or less covered with a similar bark, 

 scattered with tubercles from which the polypes are emitted. 



The spicula agree in their formation with the axis of Gorgonice, 

 being formed of numerous very thin concentric layers. Each of them is 

 surrounded and separated from its neighbour by a layer of fleshy sub- 

 stance exactly like the bark which covers the whole of them in con- 

 sistence and formation, and it is this layer which doubtless secretes 

 the thin concentric lamina of which the spicula are formed. They are 

 nearly of the same length, forming a twisted rope-like axis, consisting 

 of parallel, nearly equal, lengthened, elongated fibres, without any 

 oblique or transverse interlacing fibres or spicula. They are of very 

 different thickness, appearing as if new ones were formed, and the 

 older ones gradually increased in diameter as the coral grows. In- 

 deed the only difference that I see between this coral and Gorgonia 

 is, that instead of having a single axis, it has many twisted into the 

 form of a rope, and instead of the axis being dilated at the base so 

 as to form a kind of root, the coral lives imbedded in a sponge. 



If the fibres belong to a sponge, it is very remarkable that they 

 should never be found without the investing bark or presumed para- 

 site. I am not aware of any sponge which consists simply of parallel 

 fibres without any anastomosing or transverse filaments, nor of any spi- 

 cula of a sponge which are of different diameters gradually increasing 

 in thickness, and formed of numerous concentric layers, like the axis 

 of a Gorgonia. 



It appears to me to be much more consistent with probability that 

 Hyalonema should be a coral, than that it should be a sponge of a 

 structure never before observed, covered with a parasite also peculiar 

 in organization and new to science. 



Notice of a Hybrid Crowned Pigeon. By D. "W. Mitchell, Sec. Z.S. 



The habits of so singular a form as the Crowned Pigeon possess an 

 interest, which will, I believe, be a sufficient apology for my desire to 

 make some record of the first instance of its successful nidification in 

 confinement. And I make the record of this particular instance 

 with greater confidence, because the previous experience of the So- 

 ciety's Menagerie affords proof that the bird discovered by M. Steurs 



