7Q PERCY SLADEN TRUST EXPEDITION 



one is small and much worn, while the other is larger (14x]0x7cm.) and in better 

 condition. In this the corallites are slightly projecting and are separated from one 

 another by polygonal furrows ; about 24 septa (edges toothed but no paliform lobes) 

 meet the columella in the corallites, which are all equally thin in the calices, but 

 somewhat thickened in the walls ; alternating with these is a cycle of narrower septa. 

 The columellse are about one-third the width of the calices and formed of twisted septal 

 ti'abeculee rising into short upright rods. The costse of all the septa are similar to one 

 another, those of the neighbouring corallites usually meeting in the inter-corallite 

 furrows. 



The two examples of HeliastrcBa lamarckana in the Paris Museum are small and of 

 little use. 



Ehrenberg's two examples of Explanaria argus are small and defaced ; they may 

 probably constitute a single species along with Milne Edwards and Haime's types 

 mentioned above. 



This species differs from HeliastrcBa cavernosa in the corallites being smaller, closer 

 together, and somewhat less projecting. 



In the Paris Museum there are three more specimens named HeliastrcBa conferata, 

 which appear to belong to a different species : a large one from Guadeloupe with smaller 

 corallites than in Heliasti'cea conferata and fewer septa meeting the columellse, and two 

 small ones from St Thomas (Duchassaing) in which the columellse are much thicker. 



4. Madrepora annularis, Ell. and Sol., Zooph., p. 169, PL 53, figs. 1 and 2. 



Astrea annularis, Lam., Hist. Anim., p. 259 (non var. 2 which is Favia acropora). 

 Explanaria annularis, Ehrb., Corall. p. 84. 

 ? Orbicella annularis, Dana, Zooph., p. 214, PI. 10, fig. 6. 

 HeliastrcBa annularis, Ed. and H., Corall. ii., p. 473. 

 Madrepora stellulata, Ell. and Sol., Zooph., p. 165, PL 53, figs. 3 and 4. 

 ? Orbicella stellulata, Dana, Zooph., p. 215, PL 10, fig. 7. 

 HeliastrcBa stellulata, Ed. and H., Corall. ii., p. 473. 



? Plesiastrcea urvillei, Ed. and H., Ann. Sci. Nat., S^ser., x., PL 9, fig. 2, and Corall. ii., 

 p. 490. 



In Lamarck's type of Astrea annularis (later Milne Edwards and Haime's type of 

 HeliastrcBa annularis) the corallites are circular and slightly projecting, the calices being 

 2 — 2 '5 mm. in diameter and shallow. In every corallite about 12 precisely similar 

 septa meet the columella; alternating with these is a cycle of 12 narrower septa. 

 A pali-crown is absent. The columella is spongy. The costse are thick with transversely 

 extending granulations. 



In addition there are two much larger specimens in Duchassaing's collection (1870), 

 one from Antilles and the other from St Thomas, and a third from Antilles (collected by 

 Schramm, 1869). The remaining three examples in the Paris Museum from " mers 

 d'Indes," " mers d'Amerique," and " Australie " respectively are small and rubbed. 



Ellis and Solander's type of Madrepora annularis in the Glasgow Museum is much 

 smoothed down, but is no doubt identical with the Paris specimens mentioned above. 



