22 



with the fact that the surface of such a colonj' shows a number of smaller or lar- 

 ger patches or layers in which the single zooecia are arranged round a centre. In 

 transverse sections of colonies of the same species Waters has further seen »a con- 

 traction formed by a curved plate« placed »on each side just below the opening«. 

 I have never been able to find the two curved projections figured hy Waters but 

 sometimes two 'slender conical processes which arise from a transverse section of 

 the above covering found in the opercular area of the heterozooecia. — Of this spe- 

 cies I have examined a large number of specimens from Villedieu (Coniacian). 



Melicerilites tritblium n sp. 



? Multelea semiluna d'Orbigny, Brj'oz crét. p. G4G, pi. 739, figs. 8 — 11. 

 (PI. 1, figs. 17-19.) 



The Zooecia wich are divided by distinct marginal ridges are small, rliombic 

 or hexagonal, not so much longer than broad, and their distal part is as a rule not 

 entirely taken up by the aperture. There may be found more or less distinct tu- 

 bercles. The surface wich may be concave, flat or even a little convex is more or 

 less distinctly ascending toward the half-elliptical aperture the length of which may 

 be contained two or two and a half times in the length of the zooecium. The 

 aperture is provided with a distinct but rather narrow oral ledge and a distinct 

 perislomial thickening, and the operculum is much convex and provided with distinct 

 radiating striae. 



The Heterozooecia which may be found in very different numbers are of a si- 

 milar form and size as the zooecia; but the surface is much more concave and not 

 ascending toward the aperture. Tlie latter has a similar covering as that found in 

 the heterozooecia of Mel. magnifica. It is provided with a narrow median fissure, 

 and by a similar transverse fissure it is divided from the opercular area. 



Ooecia have not been found. 



Kenozooecia have not been found. 



The Closure is effected in the zooecia by means of a concave lamina and in 

 the heterzooecia by a filling out of the fissures. 



The Regeneration. The only form of regeneration which I have seen distinctly 

 in this species is the formation of new heterozooecia in old zooecia. In that case 

 the aperture of the latter is taken up by a large arched projection, the frontal and 

 proximal part of which is provided with a similar aperture as that found in the 

 heterozooecia, only much smaller. In old colonies I have seen a very great number 

 of the zooecia transformed in that manner. 



The Colonies are free with cylindrical branches, and in some of them I have 

 seen superficial layers of dilferent extension. 



In the presence of a similarly developed oral ledge, in the structure of the 

 heterozooecia and in the form of the colony this species shows affinity to Mel. 

 magnifica. — 



I have examined a number of fragments from Bruillé Poncé. (Turonian). 



