156 



FAMILY LIGENIDA. 



The dissociation of closely-allied types, and the approximation of types altogether distinct, 

 which result from the adoption of this scheme (and which do not less show themselves in the 

 modification of it proposed by Prof. Schultze, xcvii) will become apparent as we proceed. 

 The following arrangement of the genera is here offered as more truly representing their real 

 relationship : — 



FAMILY LAGENIDA. 

 ^ Lagena. 



Uo'h 



oigenna 



brthocerina^ 



Ijinsulina 



Rirjuiina 



llobul 



Nodosariua. 



Nodosaiia 



Dentalina 



Vaginulina 



Planuliiria 



Marginuliiia 



Dinsorpliiiia 



CrisloUaria 



Polymorphina 



I Glaiululina 



; > Frondicularia 



Flabclliua 



Taking Lai/i'iia as the primary form, it is shown to pass directly into Nodosariua, under 

 which generic designation, are brought together (for reasons to be stated hereafter), no fewer 

 than lliirtci'j/ forms which have been differentiated as generic by D'Orbigny. -Of these, the 

 seven which are ranked in the central column differ from each other only in the straightness 

 or curvature of their axis of growth, fhe transverse or oblique direction of their septa, and 

 the centricity or excentricity of their aperture. The three in the right hand column differ 

 from the preceding in the mode of setting-on of the chambers ; and the three in the left 

 hand column have been differentiated on account of the form of their apertures. The genera 

 'Poh/morpJiinaim^ Uch/crijiu being related to Logena in their essential characters, but differing 

 from each other and from Nodomrina in their respective plans of growth, have positions 

 assigned to them that arc in harmony with their mutual affinities. The small genus 

 OrtJioceriiia may be considered as a connecting link between Lngctia and the simplest 

 conditions of Vvigcruin, with relations of its own to Nodosarina. 



Genus I. — Lagena (Williamson, Figs. 5 — 32). 



236. Hialorij. — The minute flask-shaped Monothalamia which have received from 

 D Orbigny the designation Oolina, had been so long previously recognised and distinguished, 

 that it would be an act of great injustice to abandon without good reason the name originally 

 given to them. An example of them was figured by Soldani (c,ci) under the inappropriate 

 designation Orthoccra pcrfede gloMuria ; but it was by Walker (ix) that attention was first 

 particularly directed to them, several distinct forms having been figured under the generic 



