72 GOES, RETICULARIAN KHIZOPODA OF THE CARIBBEAN SEA. 



Textularia sagittula DEFR. 



Tab. IV, figg. 133158. 



The species of Textularia} are riot less difficult to define within proper boundaries 

 than are Nodosarinas. It is obvious that many gradations in the flatness or in the dis- 

 tention of the chambers will make the whole liable to numberless variations, from a 

 compressed lanceolate to a quite conical shape with either straight or sinuous margins 

 and contours. 



The shellsubstance is also variable in character being sometimes more translucent 

 and glossy, but it is usually agglutinated of calcareous or siliceous debris. In the 

 whole range of known Textularise forms it is therefore not easy to distinguish besides 

 the Gaudryina- and Verneuilina-forms more than 3 or 4 species; that is to say: 



1. Textularia sagittula DEFR. or agglutinans D'()RB., including such forms as: 

 Textul. pygmasa, Marian, carinata, cuneiformis, Baudouiana, conica, caribaaa, 

 aciculata, agglutinans, Candeiana etc. D'ORB. and a long list of names from 

 REUSS and others. 



2. Textularia gibbosa D'ORB. should be another but, it is a very ill denned 

 species; its chambers being more inflated. 



3. A third species is Textularia trochus D'ORB.; this has some tendency to be- 

 come Cuneoline. 



4. The fourth species is Textularia pennatula BATSCH., apparently representing an 

 intermediate form between the textularioid Bulirainas and the real Textularise- 



All these species have their respective Bigenerina? forms. 



Whether Gaudryiria and Verneuilina are to be considered as varieties, or 

 species, is a question that we are not yet prepared to settle, as our collections are 

 wanting in intermediate forms. 



The transverse section of our form varies from narrow oval or pointed elliptical 

 to nearly orbicular. The more sagittular form exhibits often raised bands along the 

 sutures. In older specimens the surface is more chalky and uneven. All forms that 

 we have met with are agglutinant; the shell being compactly built up of very fine 

 chalk-debris and dust. Very young ones are semitransparent, presenting a deep brown 

 tint in transmitted light; the fine granular texture of the shell concealing the pores. 

 It appears from many instances in our collection, that whenever the Textularia-stadium 

 becomes more developed, the Nodosarina growth is reduced to only one or two cham- 

 bers; and on the other hand, whenever the Nodosarina-stadium has a high development 

 the textularia-part is found to be stunted and often reduced to a few chambers. These 

 fluctuations of development give rise to a number of varietal Bigenerina-forms. All 

 our forms are composed solely of calcareous matter. 



Fiffgf 133 136: intermediate form between D'ORBIGNY'S Textul. agglutinans and 



O^> JCJ 



Textul. sagittula, and provided with one Noclosarina-chamber, the first step towards 

 forma Bigenerina. 



Figg. 137 139: the same more flattened and sagittida-\ike. 



