TRANSACTIONS OF WAGNER 



582 



TERTIARY FAUNA OF FLORIDA 



Shell solid, closed, concentrically sculptured ; ligament and resilium amphi- 

 detic, outside the hinge-plate or line of teeth ; mantle open below, with an 

 anal orifice above, but no tubular siphon ; pallial line feebly waved or entire. 



Sections : 



a. Tindaria s. s. 



Shell veneriform, not rostrate; ligament elongate, feeble, mostly posterior; 

 resilium obsolete; pallial line not sinuated. Ex. T. cytherea and amabilis Dall, 

 T. callistiformis V. and B., T. vircns, and T. sinitliii Dall (+ aincata Smith). 



b. Tindariopsis V. and B., 1897. (Type T. agathida Dall.) 



Shell more acute or even rostrate behind; ligament long; resilium short, 

 central, in a socket or excavation above the tooth-line; pallial line feebly 

 waved. Ex. T. aciinda and T. ceolata Dall. 



This section is probably to be consolidated with the next. 



C. Neilonella Dall, 1881 (+ Saiiirnia Seguenza, 1876, non Schrank, 1802). 

 Differs from Tindariopsis only in having a gap in the line of the teeth, 

 dividing them into anterior and posterior series, through which the resilium, 

 though above the tooth-line, can be seen from below. The type N. corpidenta 

 Dall is attenuated behind but not distinctly rostrate, and the pallial sinus is a 

 little more marked than in T. agathida. T. pusio Phil., Seguenza's type, is 

 distinctly rostrate, and on a casual glance hardly to be distinguished from T. 

 agathida. None of the Tindarias have an absolutely unbroken arch of teeth, 

 though between the proximal ends of the two series there is often no empty 

 space, yet the series are always distinguishable. 



d. Fseiidogloviiis T>d\\. Type Yoldia povipholyx V)d\\. 



Shell smooth, closed, thin, minute, subcircular, with the ligament short, 

 a little sunken, but visible only externally; the teeth few, in equal series, 

 .separated by a short, empty gap; pallial line .simple. 



This shell has the form of Glonais, but no internal resilium. It differs 

 from the rounded Ledas described by Jeffreys, such as sevicca, cxpaiisa, and 

 subequilattra, by the non-interruption of the tooth-line by the base of the 

 ligament, and from Tindaria proper by its orbicular shape, thin shell, and 

 smooth exterior. 



If it were worth while to name all the stages in the very uniformly pro- 

 gressive series which connects the typical Lcda with Tindaria, Malletia, etc., 

 no doubt this list of sections might be largely extended. 



