the Oenus Fistulipora, M^Coy. 



497 



In well-preserved specimens, with the aid of a lens, the 

 autopores are seen to possess a strong fold or sinus on one 

 side of the celi-aperture, raised above the general surface 

 (woodcut, fig. 2). That this fold is not superficial is proved 

 bj the fact that it occurs at all levels in the corallum at which 

 a section may be made. It is seen also in longitudinal sec- 

 tions throughout the whole length of the autopores. In a 

 transverse section this fold imparts a trilobate or floriforra 



j unction, or in other parts of the thickness of the walls, of the other tubes 

 ■were entitled " spiniform corallites " (H. AUeyne Nicholson, ' Palaeozoic 

 Corals,' Monticulipora, 1881, chap. ii.). Finding these terms incon- 

 venient for purposes of description, we propose to substitute for them the 

 following : — Autopores ( = " large corallites "), Mesopores ( = " interstitial 

 tubes "), and Acanthopores ( = " spiniform corallites"). 



The term " corallites " will be used only in a general sense when refer- 

 ring to the tubes of which the colonj"^ is made up. 



Fiff. 1. 



Fig. 2. 



m^ 



Fig. 1. — A few corallites of F. erietisis, Rom. : a, autopores ; m, meso- 

 pores ; aa, acanthopores. Enlarged about forty times. 



Fig. 2. — a. Profile view of a portion of the surface of Dekayia aspera, 

 Milne-Edw. & Haime (also one of the Monticuliporidee), to show acan- 

 thopores ; 6, the same viewed from above. Enlarged about forty times. 



There are two other words we shall have occasion to employ in the de- 

 scriptions that follow; these are "monticules" and " maculas." They 

 have been used by one of the writers (loc. cit.) and by other authors to 

 designate those minute areas or spots, either raised above the general sur- 

 face of the corallum (monticules) or a. little below it, or on a level with 

 it (maculae), which constitute the characteristic ornamentation of the 

 Monticuliporidee. It seems evident that these " maculae " and "monti- 

 cules " (consisting sometimes of cells larger than the average size of the 

 corallites) are centres from which the growth of the colony proceeded. 

 As illustrating this suggestion the reader is invited to look at the trans- 

 verse section of Fistulipora utricahts, Rominger (PI. XVI. fig. 1 c), which 

 shows (in section) one of these spots, in this instance composed of meso- 

 pores ; and the autopores, with their folds directed inwards, surrounding 

 it. This condition of things subsists throughout the entire colony. Had 

 the section been made larger it would have shown that similar areas occur 

 adjacent to each other, thus presenting a series of " maculae," around 

 which the autopores range themselves in concentric rows. 



Ann. & Mag. N. Hist. Ser. 5. Vol. xvi. 34 



