ALCYONIDzE. 375 



by the polypes are placed at the terminations of canals 

 which run through the polypidom, and which, by their 

 union with each other, serve to maintain a communication 

 between the individual polypes constituting the mass. 

 The rest of the polypidom is made up of a transparent 

 gelatinous substance, containing the calcareous spicula 

 above mentioned, and pervaded by numerous small fibres, 

 which form a sort of irregular network. Alcyonidce are 

 always attached to submarine bodies. The species already 

 mentioned is exceedingly common round our coasts; so 

 much so that, as Dr. Johnston says, " scarce a shell or 

 stone can be dredged from the deep that does not serve 

 as a support to one or more specimens." 



"The ova," writes Professor Grant, "when placed under 

 the microscope, and viewed by transmitted light, appeared 

 as opaque spheres surrounded with a thin transparent 

 margin, which increased in thickness when the ova began 

 to grow, and such of the ova as lay in contact united and 

 grew as one ovum. A rapid current in the water immedi- 

 ately around each ovum, drawing along with each all the 

 loose particles and floating animalcules, was distinctly seen 

 moving with an equal velocity as in other ciliated ova ; and 

 a zone of very minute vibrating cilia was perceptible, sur- 

 rounding the transparent margin of all the ova. The 

 progressive motion of the ova, always in a direction con- 

 trary to that of the current created by their cilia, was very 

 obvious, though less rapid than in any other zoophyte in 

 which I have observed the same remarkable phenomenon. 

 The specimen suspended in a glass jar filled with pure sea- 

 water, I now brought so close to the transparent side of 

 the vessel, that I could examine through it, with the 

 assistance of a powerful lens, and without disturbing the 

 animal, the motions and progress of the groups of ova 

 passing through the colourless bodies of the polypes. To 

 the naked eye, at first sight, all appeared motionless. The 

 deep vermilion hue of the small round ova, and the colour- 

 less transparency of the outer covering of the polypes, 

 formed a beautiful contrast with the pure white colour of 

 the delicate longitudinal folds, the central open canal, and 

 the slender filaments which wind down from its sides 

 towards the clusters of white ova at the base : but the 



