CEISINA. 
173 
D’Orbigny’s figures illustrate the occurrence of the unpaired 
median zooecia, Trhicli assign this ‘ species ’ to the group Tervia. 
Marsson includes as one of the synonyms I. calypso, Orh., which 
is more probably a synonym of Crisina cenomana, as it has been 
treated by Pergens. 
LIST OP SPECIMENS. 
Foreign. 
D. 1370. Two fragments (on slide). Maastrichter Kreide. Maastricht. 
Tine Coll. 
D. 3601. Two irregular, isolated zoaria (in tube). Maastrichter Kreide. 
Maastricht. Tan Breda Coll. 
D. 3545. Two flatter and more regular zoaria (in tube). Maastrichter Kreide. 
Maastricht. Van Breda Coll. 
D. 3544. Three fragments (on slide). Maastrichter Kreide. Maastricht. 
Tan Breda Coll. 
D. 3354. Part of a zoarium, with well -developed peristomes. Maastrichter 
Kreide. Maastricht. Van Breda Coll. 
D. 3730. Two fragments (on slide). Senonian. L’Arche de Leves. Gamble 
Coll. 
D. 6432. Four fragments (on slide). Maastrichter Kreide. St. Pierre. 
Busk Coll. 
3. Crisina (Tervia) gibbera,^ n.sp. 
Diagnosis. 
Zoarium with the branches well rounded on obverse side, and 
flattened on reverse side, on which occur isolated, thick, 
spine-like processes. The height of the processes is about 
half the thickness of the branches at the base ; they are 
as broad as the distance between two adjacent lateral series 
of apertures and taper to a sharp point. 
Apertures large, about three in each transverse series. The 
Tervian apertures are single, and one occurs usually half-way 
between the transverse series. 
Dimensions. 
Diameter of branch ... ... 1 mm. 
Diameter of zooecia ... ... ... ... '16--25 ,, 
Diameter of aperture -1--16 ,, 
Length of reverse spinal processes ... ... -5- ’7 ,, 
1 Gibber, ‘humped.’ 
