hill: geology of JAMAICA. 



245 



Turbinoseris cantabrigiensis, sp. nor. 



Plate XL,. Figs. 5-7. 



Form compressed, conical, attached by a very small pedicel. Measurements 

 of two specimens give the following : — 



The costoe are very fine, crowded, not prominent and acute, alternating in 

 size. The wall is synapticulate. There is no wall properly speaking, but the 

 many synapticulse near the peripheral ends of the septa serve as one. Of 

 course, perforations between the distal ends of the septa are frequent. The 

 septa are composed of ascending trabeculse ; the fusion between them seems 

 sometimes, but very rarely, incomplete, leaving pits or occasional perforations. 

 The septa are very numerous, extremely thin, and very much crowded; not 

 thickening at the centre. The type has between 80 and 90 septa ; the other 

 specimen, whose measurements are given above, has five complete cycles, 

 apparently 99 septa. Some septa of the higher cycles fuse by their edges to 

 the sides of the members of the lower cycles. Calice rather shallow. Strictly 

 speaking, there is no columella, a few septa fuse loosely in the axial space. 



Locality. Near Cambridge, south of Montpelier, St. James Parish, Jamaica 

 (R. T. Hill, collector). 



Remarks. The species above described, is very close to Duncan's Turbinoseris 

 eoccBTiicay^ from the limestone of St. Bartholomew. I have been unable to see 

 the types of the species from St. Bartholomew, as they are in Stockholm and 

 Upsala, therefore the following comparison is based on the original description. 

 There are two points of difference. The first is one of size. Duncan gives the 

 size of T. eoccenica, "Height of full grown specimen 1 inch (==25 mm.). 

 Length of calice -^q incli (=: 18 mm.). Breadth i^-^V ^^^^ (^^ ^^ ^^ ^^-^ mm." ^ 

 T. eoccenica is a much larger species. Duncan states that there are five cycles 

 of septa with some members of the sixth in the species ; therefore the septa in 

 T. cantabrigiensis are necessarily more crowded. The second diff'erence concerns 

 the inner terminations of the septa. Duncan says that in T. eoccenica the ends 

 of the larger septa are swollen, and bound the axial space. As stated above in 

 its description, T. cantabrigiensis does not have the ends of the larger septa so 

 swollen. The two species are close, but appear distinct. Duncan's Figure 12, 

 Plate XXL, of the costal synapticulse in T. eoccenica would apply equally well 

 to T. cantabrigiensis. 



1 Quart. Jour. Geol. See. London, 1873, Vol. XXIX. p. 558, PI. XXL Fig. 12. 



2 I have inserted the approximate equivalents in millimeters. 



