MADEEPOEA. 157 



by an increase in the thickness of the inner part of the wall, become tubular and spreading 

 (2"5 mm. diameter and 2 mm. long). The more important of these bear lateral buds. ' 



A specimen from Samoa [Mus. Godeff.) in the Strassburg Museum, referred by Ortmann 

 to M. variabilis, appears to me to approach Lamarck's types more closely than any other 

 specimen ■which has come under my notice; but the axial corallites are smaller, 3'5 to 4 mm. 

 diameter. The colony is cespitose, with stunted horizontal marginal twigs up to 2 cm. in 

 length and 6 or 7 mm. thick. The central branches are 1"5 cm. thick, and divided near the 

 base into three or more arched branchlets, 6 cm. long and 1'5 cm. thick, which are again 

 much divided and proliferous. Radial corallites very unequal, short and rather spreading 

 tubular near the apex, with short-lipped and small immersed ones between. Most of the 

 prominent corallites are 2 mm. diameter and 1'5 to 2"5 mm. long; wall a little thickened; 

 aperture somewhat oblique, and occasionally the inner part of the wall is very short. A little 

 below the apex a number of tubular corallites extend almost at right angles, and are 

 4 or 5 mm. long and 2*5 mm. thick, with buds at the base. In this situation the remaining 

 corallites are very short, and ou the main divisions nearly all are immersed, with a few short, 

 thick, spreading tubular ones between. Directive septa prominent, the others delicate and 

 often narrow. 



Indo-Pacific Ocean : Tahiti, Samoa, Tongatabu, Singapore, Ceylon. 



166. Madrepora erythraea. 



Heteropora abroianoides, Ehrenberg, Corallenth. d. roth. Meeres, p. 113. 



Madrepora erytJirma, Klunzinger, Korallenth. d. roth. Meeres, Th. ii. p. 14, pi. iii. fig. 5, pL iv. fig. 8, 

 pi. ix. fig. 10 ; Mobius, Beitr. z. Meeresfauna Mauritius, p. 45. 



Corallum cespitose, flattened or hemispherical, 10 to 20 cm. broad and 8 to 12 cm. high. 

 Branches digitiform, with numerous short proliferations, 2 to 7 cm. long and 8 to 10 mm. 

 thick, tapering a little towards the apex ; outer branches almost horizontal, free or with a 

 few fusions, and provided with distant long tubular corallites on the under surface. Axial 

 corallites 3 to 4 mm. broad ancf 1 to 1*5 mm. high. Radial corallites always with the inner 

 part of the wall undeveloped, 2 to 4 mm. long and 2 to 2-5 mm. broad ; wall rarely thickened, 

 outer part of the wall usually convex. 



In the variety cymbaformis the majority of the radial corallites are long, boat- or trough- 

 shaped ; in variety cochleariformis (Ehrenberg's type) shorter and broader with rounder 

 aperture, generally spoon-shaped. Near the base of the branches the corallites become verru- 

 ciform and immersed. Corallum rather dense within, but porous near the surface ; surface 

 spongy-reticulate or compact, echinulate ; wall substriate. 



The specimens which I have referred to this species agree closely with Klunzinger's 

 description in most respects, but all have a number of the corallites with a more or less 

 complete inner wall, and in one specimen there are many which are tubular with an oblique 

 aperture. 



Indo-Pacific Ocean : Red Sea, Maldive Islands, Mauritius, Great-Barrier Reef. 



a_c. ? ? 93. 4. 7. 134, 135, & 165. 



T 



