38 MADREPOEARIA. 



Group II.— TURBINARIiE PELTIFORMES. 

 Turbincmce in which the early cup form ieiids to be disc-shaped. 



Species 17. Turbinaria peltata. (Pis. VI., VII., VIII. ; PL XXXI. fig. 15.) 



Madrepora pdtata, Esper, rortsetzuiigen, Th. i. 1797, p. 27, Taf. xlii. 



Gemmipom peltata, Blainvillc, Manuel d'Actinol, 1831, p. 387; non Turhinaria peltata, 'EhxenheTg, 



Beit. Kennt. Korallenthiere, 1834, p. 81. 

 Gemmipora peltata, Dana,* Zoophytes, 1848, p. 410, pi. xxx. fig. 4. 

 Txirhinaria peltata, Milne-Edwards and Haime, Les Coralliaires, iii. (1860) p. 165. 

 Turbinaria dichotoma, Verrill, Proc. Essex Institute, vi. (1871) p. 89. 

 Turbinaria marima, Ortmann, Zool. JB. Syst. Abth., iii. (1888) p. 160, pi. vi. fig. 4. 



Description. — Young corallum thick, stalked, shield-shaped, concave or convex. In the 

 former case, it may in subsequent growth show all the typical foldings of more pronounced 

 cup forms, or the cup may fill up with ccenenchyma between the folds and become a convex 

 mass. The development of the early convex shield is to spread outwards and downwards as 

 an encrusting mass. 



Calicles either immersed in the rapidly growing ccenenchyma, or projecting especially on 

 protuberances and folds. In the latter case the aperture fills the top of the projection. 

 Aperture circular (varying greatly in diameter from 10 mm. (Milne-Edwards) to -4 mm.). The 

 septa are normally 2-4, but in large calicles may be 32 or more. The 24: septa can at times be 

 seen to differ in size, 12 primary and 12 secondary, while a trace of a third series is generally 

 apparent; a directive septum not infrequent. The septa rarely project even a short way 

 across the aperture, but descend almost vertically from the margin, limiting a large cylindrical 

 fossa, generally deep ; a well-developed foliate convex columella, the foli?e being either thin 

 or thick and granular, simple or divided by a directive ridge. 



The interseptal loculi, seen from above, are inconspicuous and shaped like the letter W. 

 The middle projection being caused by the rudimentary third order of septa. 



The ccenenchyma on both upper and lower surfaces with a well-marked gyrating system 

 of ridges and furrows ; wherever it is growing rapidly it is spongy in texture. 



This species is the most striking in the genus Turbinaria, and also the commonest. The 

 calicles sm-pass in size those of all other Turbinarians. 



* Dana has suggested that Ehrenberg's T. cupula is specifically identical with T. peltata, while 

 Ehrenberg's T. peltata is identical with his own T. patula. Only a reference to Ehrenberg's types 

 could decide this. I am not myself disposed to adopt the suggestion, because firstly, Ehrenberg's 

 description of T. cupula hardly corresponds \rith T. peltata ; and secondly, Ehrenberg's specimens 

 were from the Red Sea, whereas none of the numerous specimens of T. peltata and T. patula in 

 the National Collection are recorded from any nearer locality than Mauritius. Dr. Klunzinger 

 further found none in the Red Sea, but also apparently failed to find anything identical with 

 Ehrenberg's T. cupula and T. patula. These species, therefore, still await identification. 



