350 MESSRS. T. E. JOKES AND E. CHAPMAN 



in MamuUna aculeata is shown in section in fig. 41 (T), 

 where there is no septation of the internodal cavity ; but 

 the tubes are divided from the central portion by a valvular 

 septum in one case ; in another by a complete septum (this 

 may, however, be accounted for if the section were not 

 quite median) ; and at the third tube there is no septum. 

 Gault ; Folkestone. 

 23. Ramulina aculeata, Eowe Collection. — A flask-like segment, 

 which has found a. point d''appui in an ambulacral pore of an 

 echinodermal test. Chalk ; Margate. — Fig. 42. 



4. Ramulina Grimaldii, Schlumlerger, 1891. 



Figs. 43, 44. 



Specific Characters. — Test attached. Having a distinct Poly- 

 morphine commencement, and proceeding to a rectilinear out- 

 growth of great extent, which branches off laterally at almost 

 regular intervals, until it becomes less regular and loses itself in 

 large and small ramifications, sometimes anastomosed. The 

 laterals have racemose endings. 



1. SamuUna Grimaldii, Schlumberger, 1891, Mem. Soc. Zool. 

 France, vol. iv. p. 509, pi. v. — Test attached to molluscan 

 shells. The outgrowth, specified as above, is sometimes 

 eleven times the length of the commencing Polymorphine 

 series. The outgrowths are not entirely apical, but some- 

 times start from the sides of the early part of the test. 

 The initial form appears to be that of Polymorphina gihha, 

 d'Orb. Eecent; between Fayal and Pico in the Azores. — 

 Figs. 43, 44. 



