464 TUBULirORIDiE. 



lar, and the basal lamina extends beyond it : it is com- 

 monly very distinctly rugose or striated transversely. The 

 points in which it differs most markedly from D. obelia 

 are the absence of the intercellular tubules^ the indis- 

 tinctness of the zocecial outlines_, the greater regularity in 

 tl^e disposition of the cells, and (generally) their more erect 

 habit, and the presence of the closed cells with the pro- 

 jecting orifice. 



The precise significance of the zooecia (some of which 

 are generally to be met with in each colony), which are 

 operculate and furnished with the small tubular process at 

 the top, is unknown. They have been considered to be 

 subservient to reproduction, and to be equivalent to ovi- 

 cells ; but D. Sarniensis is furnished abundantly with 

 ooecia of the usual character — a fact which must throw 

 doubt on this interpretation (woodcut, fig. 24). Smitt^s 

 conjecture as to their function has already been referred 

 to (page 460) . Mr. Waters has described similar tubules 

 as occurring on his Reticulipora dorsalis {' Annals ' for April 

 1879, p. 278). 



Habitat. On shells, stones, &c., to deep water. 



Localities. Off Guernsey and Jersey (A. M. N.) : off 

 Polperro, Cornwall, 40 fms. (T. H.) : Lantivet Bay, 

 Cornwall, on Isocardia cor (C. W. P.) : Hastings (Miss 

 Jelly) . 



Geographical Distribution. ? Red Sea or Mediterra- 

 nean (R. S. Newall). 



DiASTOPORA SUBORBICULARIS. 



Plate LXVI. figs. 11, U o. 



DiASTOPORA SIMPLEX, Busk, Crag Pol. 1 13, pi. XX. fig. 10 : Smift, loc. eit. 396 

 & 42.3, pi. viii. figs. 7, 8. (Not, Discosparsa {Diasfopora) 

 simplex of D'Orbigny.) 



