GENERA OF FAVOSITID^E. 113 



Vermipora clausa, Lindstrom, sp. 

 (PI. VI., figs. I- I b.) 



Spec. Char. — Corallum forming small sublobate or subramose 

 masses, composed of nearly cylindrical corallites, which diverge 

 from an imaginary central axis. Centrally the corallites are in 

 close contact, and are rendered subpolygonal by mutual com- 

 pression ; but as they diverge outwards, they become, as a 

 general rule, more or less completely free, each being enclosed 

 by its proper wall. Diameter of the corallites about half a line, 

 the intercalated younger tubes of all sizes below this. Walls 

 thick, perforated at all points where the corallites are in con- 

 tact, by numerous irregularly-distributed, circular mural pores. 

 Septa well developed, in the form of radiating spines. Tabulae 

 well developed, complete, mostly horizontal, or curved with 

 their convexities downwards. 



Obs. — As before said, I am indebted to Dr Lindstrom for 

 examples of this species, with the \?^^q[ oi Favosites claustis ; 

 and I presume that it is a portion of a specimen of this form 

 which he has figured in a paper on certain Zoantharia Rugosa 

 in the ' Ofversigt Vetenskaps- Akademiens Forhandlingar ' for 

 1856, PI. XXXI., fig. 14, under the name of Fletcheria clmtsa. 

 I have not access, however, to the original of this paper, and 

 do not know if Dr Lindstrom has published any full description 

 of the species. 



In general appearance the corallum of Vermipora clausa 

 might well be taken for a small dendroid Favosites, which 

 has a tendency to assume rather a lobed than a truly branched 

 character. The largest specimen I have is about ten lines in 

 length and five lines in its greatest width. The internal struc- 

 ture is also precisely that of Favosites proper ; and the only 

 point which justifies generic separation is to be found in the 

 fact that the tubes invariably become more or less cylindrical 

 and more or less completely free as their mouths are ap- 

 proached (PI. VI., fig. i). In the amount of this freedom, 

 however, there is considerable difference in different speci- 



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