L7l Ml(. A. W. WATIOltS ON 



d'Orbigny wIkmi lie wjiys " Uuil; gtMuiw wan roiuidod by d'Orbigiiy 

 in 1810 ibr Iho Apsendesia lUantlma of Jilaiiivillc, which is a 

 Ealhoiiian HpccicB." Wo now know that d'Orbiguy niado a 

 iiuHtako in ])Lu'ing tho A. diantlius under BeticuUpora, and that 

 it d()(>H not tit all cOTTet^])ond with liis diagnosis of tho genus. 

 Taking as tho typo tho spot-ios that was iiivst nioutioued, bocause 

 it was geologically tho ohU^st, would add much to the present 

 conruHion, an this cawo donionHtratos ; for all i\w JRciiculipora woll 

 (UiHcriluHl ai\d llgurod by (l'()rl)igny aro not allovvod to roniain in 

 his genus, whiU^ another species nioroiy iiientioncd, whicii doew 

 not correspoiul with his description of tliegonus, is made iJie ty [)o 

 o^ lieliculipora ot (Jregory (non d'Orb.) ; and tlien in (Gregory's 

 Catalogue iiio llolosloiiia coniiinjrni^^ lionsihilo, is [)hu'ed under 

 Reticulipont. 



In Diastopora llio /ouH'ial tubes aro small, whereas in Slomato- 

 pora thoy aro usually larger with much thicker walls. It is only 

 in 7)/«.s70jjJ0'/'« (used iu a wide souse) that tlio "closure" has a 

 small tubulo iu tho middle ; and such closures aro now known in 

 Diasfopora snriiicnsisy Norm. ; B. conciirna, Macd. ; Itcticulipora 

 mwimiiJ/'forimi, d'Orb. ; li. oOlujua, d'Orb. (^Cretaceous) ; li. papi/- 

 racca *, d'Orb. (Cret.) ; It. dorsalis, Watois ; Mesenteripora 

 rtpanti, HaswcOl ; Mexoitcripora mcandrina., !S. Woods ; Diaafo- 

 pora (jnlla, Jul!. & Calvol. 



There aro a low species wiiich !ia,v(^ " adventitious tubules " 

 {Bush) called zoa^'inlos by Jullion, as for oxani])lo D. obella, 

 Johnst. ; JJ. liif.rican'a, Sniitt ; JJ. hrciidolensis, Waters; Diplo- 

 pora Qrmaldi, Jull. & Calv. The closures of the species of this 

 grou|i, so far as they aro known, have numerous perforations (see 

 IM. 19. lig. 7), and to none of tho closures is there a tubule. It 

 is unfortunate that tho term tubule has boon employed in the 

 samo genus for quite dilleront structures. 



In D. intricaria tho adventitious Uibnlos arise from the space 

 foruuMi over tho groups of zoax'ia by a second calcareous layer, 

 as shown iu IM. 19. ligs. 1), 10. 



In the adventitious tubules oC/X ohelia there is a protoplasmict 

 mass, pa^sing thnuigh a gron[) ot" muscles, but this I have not 



* Tliis ooeiirs in Vi'. ohliqua, d'Orb., fossil J'roui Tours aiul I'roin LaBoime- 

 \illo; and in li. ^xipip'ucm, d'Orb., IVoin La ISonneville. 



t I'ergens, " Bry. du Cr6t." 13uli. Soo. lilolgo do 06ol. vol. iii. p. ."^ll, f!g. 4 ; 

 Wutoi'y, " Norl,h llul, Bry.," Quart. Jourii. Oool. Soc, vol. xlviii. p. 155. 



