si T.-oHDER D 



CHILOSTOMATA 



tin- lower part of the peristome elevated into a more or less prominent mucro. Tertiary 

 oent 



>v//r.ny ,.,,,//,,, Ilinrks. Zoaria variable; zooecial orifice varying from semi-circular 

 t.i Mil.-orbicular, tin- lowi-r margin with ;i di.-tinct sinus. Cretaceous to Recent. 



FIG. 483. 



Lepralia pallasiana, Moll. 

 i'i-ciit ; England. 



highly 

 Hincks). 



nagnified 



Zooecia 

 (after 



Fio. 484. 



Mucronell'i cocci net', 

 Abildg. Miocene; Eisen- 

 stadt, Hungary. A num- 

 ber of zocecia enlarged 

 (after Reuss). The aper- 

 tures are denticulated, 

 and each zooecium has a 

 pair of avicularia. o. 

 Ovicell. 



Fio. 485. 



Schizoporella cum nt, 

 G. and H. sp. 

 Pliocene ; Santa Bar- 

 bara Co., Cal. Zooecia 

 highly magnified 

 (after Gabb and 

 Horn). 



Retepora, Imperato (Phidolophora, Gabb and Horn), (Fig. 486). Zoaria consisting 

 usually of inosculating branches which spring from an encrusting base. Zooecia dis- 

 posed on one face of the branches only, in most cases immersed. Primary orifice 

 rounded or semi-elliptical with entire border. Afterwards the peristome becomes much 



FIG. 480. 



Eettpora celltilosa, Linn. 

 Suffolk, England. 



Crag 



FIG. 487. 



Mi/ri/^iinni i>nnct<i.tHm, Phill. sp. Miocene; Ortenburg, Bavaria. 

 A, Zoarium, Vi- #, Upper surface, enlarged. In the forward portion 

 the apertures are open , in the rear, covered over by a calcareous 

 deposit. V, Cross-section of a branch. 



raised and multiform ; usually there is a fissure below, or there may be a prominent 

 rostrum bearing an avicularium. Tertiary and Recent. 



? Myriozoum, Donati (Myriopora, Blv. ; Vaginopora, Reuss), (Fig. 487). Zoaria 

 consisting of thick, dichotornously dividing branches, obtuse at their growing ex- 

 tremities, and rising from an attached basal expansion. Zooecia disposed about an 

 imaginary axis, even at the surface, their boundaries scarcely distinguishable. Entire 

 surface and also the inner walls minutely porous. Orifice above the centre of the 

 zooecium, sub-orbicular, notched, or canaliculate below. As a rule, the openings are 

 closed on the lower parts of the branches by a calcareous pellicle. Tertiary and 

 Recent ; perhaps also Cretaceous. 

 VOL. I 



