PHOTOTYPE PLATES NOS. XXIII. AND XXIV. 37 



stalk, from which it subsequently breaks free. This chapter in the life histor}- of the 

 Feather-star has justified the conjecture that its original progenitors were permanently stalked 

 like some of the few existing Crinoids, and exceedingly numerous fossil Encrinites, or Stone- 

 lilies. It may be analogously surmised as probable that the existing unattached Mushroom- 

 corals are the specially-modified descendants of a pre-existing, permanentlj'-stalked coral-stock. 

 What form this simpler ancestral t3-pe was represented by cannot at present be accurately pre- 

 dicted ; but it is probable that, as in the case of the stalked Crinoidea, it attained to its maximum 

 of development in the tranquil abysses of the ocean. 



A point of interest has to be recorded in association with the reproductive phenomena of 

 the Mushroom-coral. It has been discovered that the stalk, after the separation from it of the 

 terminal tentaculiferous disk, is by no means dead. Portions of the somatic tissue and of the 

 septal elements are left behind ; and these sprout anew, and produce, in course of time, similar 

 discoidal coralla. The specimen figured in the accompanying plate indicates very distinctly, 

 by the scar and ragged septal edges exposed to view a little beneath the expanded disk, the line 

 of demarcation across which the preceding young corallum became separated. By virtue of 

 their reproductive functions, the title of " Nurse-stocks " has been conferred upon these growth- 

 forms of the genus Fungia. With reference to this plan of reproduction, the phenomena de- 

 scribed undoubtedly correspond very nearly with those of the " Strobila " form of the Hydroid 

 polyp, Cyanca capillata in which multiplication is similarly accomplished by repeated transverse 

 segmentation and detachment. A somewhat abnormal example is figured in association with 

 Plate VI. of the coloured series, in which two young Fungia are in course of development 

 from the truncated end of a simple cjdindrical Nurse-stock. All the examples of this Mushroom- 

 coral figured in both the coloured and the accompanying photo-mezzotype plate were obtained 

 from the fringing reefs of Adolphus Island at the entrance to Torres Strait, and were photo- 

 graphed in baths and other receptacles on board H.M.S. Rambler, then engaged in surveying the 

 ground around the scene of the Oitctfa wreck, in which cruise, with the object of studying the 

 fish and the coral fauna of the district, the author was privileged to travel as Captain Dawson's 

 guest. 



PLATE XXIV. 



MUSHROOM-CORflLS, flTTICHED, YOUNG, AND FULLY-EXPINDED STSTES. 



The lower (jf the two illustrations in this plate represents a group of the same species of 

 Mushroom-coral, Fungia crassitentaailata, that occupies the entire area of the preceding plate. 

 The individuals composing this group were originally collected at Adolphus Island in asso- 

 ciation with H.M.S. Rambler's cruise, and were thence transported to one of the pearl-shell 

 cultivation pools of the Thursday Island reef. In this situation they soon made themselves 



