274 DESCRIPTION OF CHALK CORALS. 
blance with the Criserpia of that authority! exists, but in the development of the 
tubes, the agreement is with Diastopora, the additions in Criserpia, if rightly 
understood, springing in the typical species C. Michelini from the side or towards 
the lower extremity of a previous tube, and not from the upper end. The only 
specimen examined was barely visible to the unassisted eye, and was attached 
to the same Micraster as Epiphaxum auloporoides and Alecto ramea? ; it was also 
intermingled with them. The greatest extent in the direction of the oppositely 
diverging branches, measuring the chord and not around the arc, was under two 
lines, and the width of the largest fan-shaped portion was scarcely half a line. 
Clypeina tubeformis, n. sp. (Tab. XVIII. A. figs. 4 & 4a.) 
Trumpet-shaped ; stem long, cylindrical, traversed vertically by lines defining 
the range of the visceral tubes, and transversely by irregular furrows ; expanded 
portion smooth on the under surface, but streaked by upward extensions of the 
divisional lines of the stem, also encircled by fine grooves ; margin of the expan- 
sion provided with two or three rows of tubular apertures ; interior of the funnel 
ribbed, and indented with transverse lines similar to those on the exterior ; floor 
broad, slightly convex ; base of the coral an irregular expansion of the stem, 
and like the latter tubular. 
Under the designation Clypeina marginiporella M. Michelin® has described 
and figured a curious, minute tertiary fossil, found in the Paris basin. The 
specimen delineated in the ‘ Iconographie Zoophytologique’ agrees generally 
with the upper portion of Mr. Dixon’s coral (fig. 4), the chief difference con- 
sisting in the rows of tubular openings on the margin of the funnel exceeding 
one in the English zoophyte : Clyp. marginiporella terminates, moreover, abruptly 
where it assumes a cylindrical outline, and it is stated to adhere ‘“‘ par une 
espéce de petite lamelle circulaire ;”’ the tubular structure is also apparently 
confined to the dilated portion, no trace of such a composition being represented 
in the inferior annular edge of M. Michelin’s figure 27 6; whereas in Clyp. tube- 
formis, small tubuli are visible in the fractured margin of an expanded base. M. 
Michelin expresses a doubt respecting the nature of his fossil, and asks, ‘‘ Est- 
ce un polypier ?”’ No doubt however is entertained of the English body belong- 
ing to the class Bryozoa or to Ascidian polypes, and to the family Tubuliporide ; 
' Annales des Se. Nat., 2nde sér. Zool. tome ix., or Recherches sur les Polypes, Mém. sur les Crisies, 
&e., pl. 16. fig. 4. 
2 Iconographie Zoophytologique, p. 177. pl. 46. fig. 27. 
