358 BULLETIN 106, UNITED STATES NATIONAL MUSEUM. 



Occurrence. Vicksburgian ("Chimney rock" of Marianna limestone): One 

 mile north of Monroeville, Alabama (abundant). 



Vicksburgian (Red Bluff clay) : Seven and one-half miles southwest of Bladen 

 Springs, Alabama (rare). 



Cotypes.Cnt. No. 64271, U.S.N.M. 







SCHIZOMAVELLA LONGIROSTRIS, new species. 



Plate 85, fig. 13. 



Description. The zoarium is free, bilamellar, very small; the two lamellae are 

 easily separable. The zooecia are elongated, distinct, oval; the frontal is convex 

 and formed of a tremocyst with large pores. The aperture is orbicular or trans- 

 verse; the anter is large and semihmar : the rimule is wide and concave. The ovicell 

 is globular and salient; its orifice is always closed by the operculum. The median 

 avicularium is long, salient, provided with a pivot and a long triangular beak. 



,, ] IIM u.j.umiu. . f Zs=0.65-0.80mm. 



Measurements. Aperture 1 , Zooecia \ , 



Uffl=0.12 mm. 1/3=0.40 mm. 



Affinities. We possess only a few small specimens of this species, and it has 

 therefore been impossible for us to make a careful study of it. It appears to present 

 some interesting peculiarities in its ovicell and in the disposition of its large 

 avicularium ; but it is necessary to await more material. 



There is a similar recent species, Schizoporella longirostrata Hincks, 1882, but 

 its avicularium is not median. 



Occurrence. Vicksburgian (Red Bluff clay) : Red Bluff, Wayne County, Mis- 

 sissippi (rare). 



Holotype.Cnt. No. 64264, U. S. N. M. 



SCHIZOLAVELL-V new genus. 



The ovicell is closed by the operculum. The operculum bears a variable 

 rimule. The frontal is a tremocyst. There are two lateral avicularia. 



Genotype. Schizoporella vulgaris Moll, 1803. 



Range. Rupelian Recent. 



This genus differs from Schizomavella only in the lateral position of the avicu- 

 laria and in the muscular attachments of the operculum, which are more distant 

 from the border. 



The functions of the avicularia seem to be multiple: but they are not well 

 known. The generic divisions based on these organs always present a relative 

 uncertainty which only further studies can eliminate. 



The fossil species of this same genus are : 



SchizolavelJa (Eschara) phymatopora Reuss, 1869. 



Schizolavella (Lepralia) schizostoma MacGillivray, 1895. 



1 ror=abbreviation of " lateral avicularin." 



