194 FAMILY GLOBIGERIXIDA. 



alternate with each other. The aperture consists of a number of distinct pores arranged 

 in a single series along the whole extent of the apertural plane, as in the most flattened form of 

 Peneroplif! ; and these are so obliquely disposed, that each chamber communicates by their 

 means with the alternating chambers below and above it in the opposite series. 



328. Affinities. — It is obvious from the preceding description, that CuneoJina is nothing 

 else than a Tcxtidarin which is extremely compressed in a direction transverse to the normal 

 direction of its compression ; for if we could imagine a Textularia with globose chambers to 

 be composed of a plastic substance, it can be easily conceived that whilst by pressure applied to 

 the two axial /«ci"5, those two faces might be extended and thinned out until they presented 

 the flat triangular shape which distinguishes CuneoUna — each face being divided by the axial 

 line, on the two sides of which the two series of chambers would still be disposed, — a 

 like pressure applied to the two margins would flatten the two series of chambers 

 against one another, so as to convert what were before the margins into lateral faces, 

 and to bring to what were before the axial faces into the condition of margins, as occurs in 

 certain aberrant Biloculincp. The same change would convert the wide crescentic aperture of 

 the ordinary Textularia into a narrow elongated fissure ; and it is obvious that the conversion 

 of this into a row of detached pores does not in itself remove CuneoUna further from the 

 Textularian type, than Peneroplis is distant from Dendrifina, or Calcarina from Motcdia. 

 Intermediate gradational forms being iiere wanting, however, CuneoJina must, for the present 

 at least, be ranked as distinct Irom Textularia, though in close proximity to it. 



Genus XL— Bulimina (Plate XII, figs. 18—22 ; and Williamson, Figs 124—135). 



329. History. — ^The peculiar type to which the name Bulwmia (expressive of the Bulimus- 

 like form of its spire) was given by D'Orbigny (lxxiii) in 1825, does not seem to have been 

 recognised by any preceding systematist. It has been since generally adopted in tlie sense 

 in which it was originally employed ; but we shall use it as the generic designation not merely 

 for the forms included under Bulimina proper, but also for those belonging to the sub-genera 

 Virgulina and BoUvina, which were instituted as genera by D'Orbigny, but were regarded by 

 him as allied rather to Textularia than to Bulimina. 



330. External Characters and Internal Structure. — In its typical form the shell of 

 Bulimina is composed of a series of spheroidal segments progressively increasing in size, and 

 so applied to one another by their flattened faces as to form a " bulimine" spire (Plate XII, 

 fig. 18). The aperture is a loop-like notch in the convex wall of the last chamber, 

 extending forwards and outwards, usually with more or less obliquity, from its umbilical mar- 

 gin ; its shape is such that it seems as if it were formed by the folding over and convergence 

 of the two halves of the anterior wall of the chambers (Plate XII, fig. 18), and it is noticeable 

 that these do not commonly meet at the umbilical angle, but that one passes obliquely behind 

 the other. The margin of the aperture is usually somewliat lipped externally ; on the other 

 hand, it is sometimes prolonged externally into a little narrow tubular neck. The shell of the 

 smaller forms and younger specimens of Bulimina is hyaline and very translucent, and it's 



