142 MONOGRAPH OF THE FOSSIL POLYZOA. OF THE 



The special pore is placed alternately at the right and left hand, distal angle of the 

 cellule, in each longitudinal series. It is bordered by a distinct, thickened lip, nar- 

 rowest at the end near the mouth. 



From the Miocene ; Petersburg, Va. 



The only colony we have seen is of an elongated, pyriform shape, covered with 

 large regular elevations, over which the cellules run without changing their course. 

 There is a hole on one side which may be the cavity left by a tube of a Serpula, over 

 which the colony is encrusted, or it may have been caused by some boring animal. If 

 the latter is the case, it will probably prove that the genus is erect in its mode of 

 growth. We are inclined to this opinion because of the very regular form of the 

 colony. Whether the pyriform or clavate shape is peculiar to the species, we cannot 

 determine until we see more specimens. It is probable that the species retains more 

 or less of an approximation to the form. 



Subfam. PORELLINiE, d'Orb. 1851. 



DISCOPORELLA, d'Orb. 1851. 



* Colony discoidal, fixed in its young state generally to a grain of sand, which be- 

 comes eventually imbedded in the testaceous substance of the colony. Cellules on 

 the upper surface only, which is convex, the lower surface is concave and radiately 

 striate. Cellules arranged in radiating lines and quincunx; surface pierced by regular 

 transverse or radiating fossets placed posteriorly to the mouth. Mouth anterior, a 

 special pore placed always before the mouth. 



This genus can be distinguished from all the other free discoidal forms by the cel- 

 lules possessing regular fossets pierciug the surface of the cellule, and by the presence 

 of a pore in advance of the mouth. 



D. denticulata, G. and II., fig. 25. 



Lunulltes denticulata, Con., Sill. Jour. vol. 41, p. 348. 

 L. depressa, Con., id. 



L. denticulata, Lonsdale, Quart. Jour. Geol. Soc. vol. 1, p. 503. Id. d'Orb., Prod. 

 Pal. vol. 3, p. 136, No. 2578. Id. Emmons, Report Geol. N. Car., p. 311, 

 figs. 248, 249. Id. Tuomey and Holmes, Pliocene S. Car. p. 11, pi. 4, f. 

 1—5. Id, Holmes, Post. PL S. Car. p. 6, pi. 11, f. 4. 

 ? Dlscoporella umbellata, Emmons, (not d'Orb.), Rep. N. Car. p. 312, figs. 254, 255. 

 Colony discoidal, outline varying from circular to elliptical, upper surface convex, 

 sometimes half as high as wide and at others very depressed ; under surface concave, 

 nearly parallel with the superior face. Cellules subhexagonal, variable in form, ar- 

 ranged in an oblique quincunx, separated by a prominent, angular, thickened wall 

 projecting considerably beyond the surface of the cellules, ending in a shaiqs crest and 



