BemarJcs on the Foraminifera. By Prof. T. Bujoert Jones. 73 



as in Cristellaria, &c., and of margins, as in Vaginulina, &c. 

 (" limbation ") ; or over the crossing of septa, as in scabrous Nurn- 

 7nulinie, and in umbonate Amphisteginse ; also in the umbihcus 

 of Boialia. 3. Local hypertrophy of the shellsubstance, with 

 branching tubes, continued from the annular and other canals, in 

 the thicker shells; as in the radiate processes of Tinoporus, in 

 the umbones of Polysiomella, and in the processes and umbones 

 of Galcarina. 4. The outward extension of the narrow walls, or 

 intervallation, of the tubuli, making their edges sharp and rugged, 

 as in old Globigerinm, and even prolonging them into thickets 

 of long, thin needles, as in the acerose and hispid Glohigerinae and 

 Orhulinpe, rivalling BadioJaria in their radiate growth. Other 

 modifications of this superficial shellgrowth among the pseudopodia 

 are seen in some PlanorbuUnai ; and the shellmatter sometimes 

 sheaths the roots of the pseudopodia in very hirsute Calcarinie, also 

 occasionally in Texfularia and Planorhulina. In an extreme degree 

 it involves the terminal processes of sarcode in Polymorphina 

 Jwrrida ; and not unfrequently makes an apertural tube, giving a 

 pouting orifice to TJvigerina, &c. 5. The formation of subsidiary 

 flaps, tenthke projections, and chamberlets for umbilical sarcode, is 

 frequent, as in asterigerine Discorbinee. Such secondary segments 

 are neatly packed among the chambers in Amphistegina.* 



Endless modifications of external appearances are brought about 

 by the various developments of these and other habits of growth ; 

 and the extremes produced by each kind of growth may seem at 

 first sight to have little or no relation one to another. 



The method in which the shelly coatings of successive segments 

 meet each other, — singly, in the simple tentlike setting-on of the 

 new chamber ; doubly, with more or less continuous enwrapping of 

 the new segment in shellmatter; or double with intermediate 

 canaliferous substance, — does not now immediately concern us, 

 though at the foundation of many modifications of form. 



Lagenida. — The Cristellarians, whose variability we have 

 especially to illustrate, belong to the Lagenida. This large group 

 comprises, besides EUipsoidina, of obscure relationship, the Lagenx, 

 the Nodosarinae, and Orthocerinai. Polymorphinee and Uvigerinse 

 have very little distinctive character to separate them from this group. 



Lagena. — The very common Lagense are mere flasklike shells, 

 exquisitely delicate, presenting endless and generally elegant modifi- 

 cations of form . Always of simple construction, Lagena, nevertheless, 

 has its surface occasionally beset with rough granules of shellmatter, 

 and even overcast with a coating t which the outer sarcode may be 

 said to have laid down in abortive eff'ort to procure the '• supplemental 



* The examples here offered for these inequalities of siirface are not to be 

 regarded as exhaustive. 



t ' Phil. Trans.,' vol. civ., p. 420, pi. 18, fig. 7. 



