458 TUBITLIPORID^. 



of growth is only a slight variation on that which we have 

 in the section of the latter genus represented by T. flabel- 

 laris. It agrees with it in being destitute of cancelli ; 

 whilst in the comparatively depressed and immersed con- 

 dition of the zooecia it has a parallel in certain forms of 

 Stomatopora. 



The genus Diastopora has^ however^ on the whole^ a 

 very distinct facies. The expanded crustaceous mode of 

 growth, the prevalent tendency to assume a discoid or 

 flabeilate form, the immersed and crowded condition of 

 the (usually) slender zoceeia, are characters which com- 

 bine to give it a very decided individuality. 



The erect and foliaceous forms, which have been ranked 

 under Mesenteripora, Blainville, are included in the pre- 

 sent genus as here defined. 



Diastopora patina, Lamarck. 

 Plate LXVI. figs. 1-6. 



TuBui-ii'ORA PATINA, Laink. An. s. Vert. ed. 2, ii. 244 : Blainville, Actinol. 



425 : Johnst. B. Z. ed. 2, 260, pi. xlvii. figs. 1-3 : Gosse, 



Mar. Zool. ii. 8, fig. 1 : &c. 

 Patinella verrucaria, Gray, Br. Bad. 138. 

 Patinella patina. Busk, Bep. Brit. Assoc. 1859, Trans. Sect. 147 : Hincks, 



Dev. Cat. loc. cit. 468. 

 Discosparsa marginata (prolilerous ioYm.),D'Oi-h. Pal. Fr. terr. cret. v. 822, 



pi. dccivii. figs. 5-10. 

 Discosparsa patina. Heller, Bi-yoz. d. Adr. M. 46. 

 Diastopora patina, Smitf, loc. cit. 397 & 426, pi. viii. figs. 13-15 : Busk, 



B.M. Cat. iii. 28, pi. xxix. figs. 1, 2, pi. xxx. fig. 1. 



Zoarium discoid, circular, or (sometimes) elliptical, more 

 or less cup-shaped, or flat and entirely adherent, sur- 

 rounded by a rather broad extension of the basal lamina, 

 forming a thin white border, transversely lineated. 

 Zooecia stout, minutely punctate, crowded, in the central 

 portion of tlic colony immersed and closed, disposed in 



