174 MONOGRAPH UF THE FOSiSIL POLYZOA OF THE 



branches. Each cellule provided with an " accessory pore " placed below the opening. 

 Back pierced by " opposed pores." 



The presence of the " accessory pores " distinguishes this genus from Crisvna, and 

 the transverse arrangement of the cellules separates it from Hornera, in which the 

 rows are placed longitudinally on the branches as in Gavea. 



B. Abbotii, G. and EL, fig. 65. 



Heterocrisina id.,G. and H., Jour. Acad. Nat. Sci. Philada., vol. 4, 2d ser., p. 404, 

 pi. 69, fig. 45, 46, 47. 



Colony, small, composed of flattened, subquadrate branches. Cellules arranged in 

 transverse lines on the sides, with the most anterior one largest, looking forwards or 

 obliquely outwards. Lines usually alternating on opposite sides. Openings, when not 

 worn, round ; a small elongated pore below each opening, causing the appearance of 

 flutings between them. Surface between the rows of cellules, excavated, concave, 

 smooth. Back of the colony coarsely reticulated, with irregular pores scattered pretty 

 closely. 



Section of branch, showing numerous germs of cellules. 



Common near Mullica Hill, N. J. Cretaceous. 



The species was first described from a series of somewhat worn specimens, which 

 misled us, in the generic characters. The anterior row of cellules was abraded in such 

 a manner as to present oblique alternating rows. Having since obtained more perfect 

 specimens, showing the unworn state of the colony, we are happily able to correct the 

 unfortunate blunder thus made. 



In most cases the rows of cellules are not directly transverse, but are inclined a 

 little downwards. The anterior surface of the branches is usually excavated, and the 

 branch is widest behind. 



CEISINA. 



Colony in free branches, bearing two rows of cellules, interrupted in the middle. 

 No accessory pores. 



Differs from Filicrisina in the two interrupted lines. In the latter genus, there is 

 but one line of cellules without interruption. From the preceding genus, it is dis- 

 tinguished by having no accessory pores. 



C. sereata, n. s., fig. 66. — Colony in flattened, filiform branches. Cellules arranged 

 along the edge, prominent at its distal end, sloping downwards and inwards towards 

 the proximal end. Opening circular, bordered by a thin, sharp rim, often projecting 

 directly forwards at a right angle with the branch. Lateral edge of the cellule 

 straight, convex or concave. Surface of the colony, anteriorly, carinate longitudinally 

 in the middle, rarely convex, with the surface sloping towards the edge. Back 

 regularly convex or carinate, more prominent than the front, often grooved between 



