ON THE POSTEMBRYONIC DEVELOPMENT OF CYCLOSERIS. 



By J. STANLEY GARDINER, M.A. 

 With Plate XIX. (Figs. 10—14) and Plate XX. (Figs. 15—24). 



When the alternation of generations in Fungia was first described by Stutchbury 1 , 

 the species of Cycloseris, then known, were placed under that genus or the genus 

 Cyclolites. Milne-Edwards and Haime, in 1849, separated the genus Cycloseris 2 , and, 

 in 1851, carefully considered and described its species 3 . In the work last referred to, 

 the genus is described as follows : — " Polypier simple, libre et sans traces d'adherence, 

 etc." In 1848, the same authors had previously described with a plate the septal 

 arrangements in the different postembryonic stages of Fungia patellaris and Fungia (now 

 Cycloseris) hexagonalis', apparently believing that the development proceeded by similar 

 stages in both species. Among the specific characters of the latter species, however, 

 there is the statement " on ne distiugue aucune trace d'adherence meme dans les tres- 

 jeunes individus 5 ." 



In 1879, Tenisou- Woods described a young detached specimen of Cycloseris sinensis', 

 and further stated that a central disk on the under surface " is found on the lower 

 part of every Australian specimen." Quelch considered that the form referred by 

 Tenison- Woods to Cycloseris sinensis was more closely allied to Cycloseris discus and 

 Cycloseris freycineti 7 ; he neglected, nevertheless, to mention the fact that some of 

 the Challenger specimens of that species have a very distinct scar on the aboral 

 surface. Bassett-Smith, however, found among his corals from the Tizard and Maccles- 

 field Banks young fixed forms of Cycloseris tenuis and Cycloseris sinensis*. 



Considering that similar stages to those, so carefully and accurately described for 



1 "An Account of the Mode of Growth of Young Corals of the Genus Fungia," Trans. Linn. Soc, 1830, 

 p. 494. 



2 Compt. rend, de l'Acad. des Sci., t. xxix, p. 72. 



3 Ann. des Sci. Nat., Ser. 3, t. xv, p. 111. 



4 Ann. des Sci. Nat., Ser. 3, t. ix, p. 37, PI. vi. 



1 Ann. des Sci. Nat., Ser. 3, t. xv, p. Ill, and Cor. in, p. 51. 



6 Proc. Linn. Soc. of N. S. W., vol. in, p. 20. 



' Beef-Corals, Challenger Eeports, p. 122. 



8 Ann. and Mag. Nat. Hist., Ser. 6, vol. vi, p. 446 (1890). 



24—2 



