26 



are not developed. The aperture is provided with a very distinct, but rather nar- 

 row oral ledge, but a peristomial thickening is very seldom distinct, being in most 

 cases coalesced with the surface of the small, triangular mostly convex *suboper- 

 cular area the height of which in most cases is contained about two times in tlie 

 height of the aperture. The apertures placed in the same transverse series are in 

 most cases divided from each other by columnar projections wholly or partly 

 formed by the lateral parts of the peristomes. The operculum is convex witli di- 

 stinct radiating striae. 



No Heterozooecia. 



No Kenozooecia. 



Ooecia have not been found. 



The Closure as a rule takes place in a very singular manner. It starts by an 

 enlargement of the oral ledge, and at the same time the distal and the proximal 

 margins of the latter get connected by a number of vertical columnar projections 

 divided by rounded pits. As this distal closure-plate gradually increases in size 

 and in thickness the pits increase in length, at the same time diminishing in 

 breadth, and the oral ledge thus gets transformed into a strongly arched structure 

 very much like a cheilostomatous ooecium or an eye-lid. According to their age 

 these distal closure-plates are either smooth or their surface presents a series of 

 more or less distinct impressions, the vestiges of the original pits. Somewhat later 

 than the distal also a proximal closing plate begins to develop, starting from the 

 proximal margin of the aperture. In opposition to the distal plate the latter is as 

 a rule concave or flat, and sometimes directed obliquely inwards. By and by the 

 originally large aperture is transformed into a narrow fissure-like opening which 

 is lastly filled out. This process of closure, however, shows a great variation even 

 in the same fragment, the two plates being developed in very different degree, and 

 in some cases the distal one may be very small (figs. 1, 9). In a few zooecia I 

 have found the closure effected in the usual way by means of a concave or flat 

 lamina (fig. 2). 



Regeneration has not been found. 



The Colonies are free with cylindrical branches, and I have seen no superficial 

 layers. 



I have seen rather numerous specimens of this species from Villedieu. 



Meliceritites Lorieri d'Orbigny. 



Vincularia Lorieri d'Orbigny, Bryoz. Cret. p. Gl, pi. (501, figs. 18 — 20. 



Melicertites semiclausa Pergens, Revision d. Bryoz. p. 394. 

 non Melicertites semiluna d'Orbigny, Bryoz. Cret., p. 623, pi. 736, figs. 20 — 21. 

 non Melicertites semiclausa Gregory, Cretac. Brj'ozoa, p. 328, pi. XIV, figs. 1—3. 



(PI. IV, fig. 18.) 



The Zooecia which are at the utmost as long as broad and in most cases a 

 little broader than long are not divided by distinct marginal ridges, and the peri- 



