(JKAl'TOLITES OF NEW YOUK, PAUT 1 723 



D. teretiusculus Hisinger sp. Freeh describes [1897, p.628] a form 

 from a north German glacial boulder with thecae projecting " swallow-nest- 

 like " as D . s e r 1 11 1 ii r i o i d e u s . With that species our specimens 

 specially those which were apparently slightly macerated before becoming 

 buried [pl.l6, fig.Sj, possess some similarity in the shape of the thecae. 

 The consideration of a possible identity of the two species is however 

 precluded by the slenderness of the rhabdosome of our form when 

 compared with the broader and more compact shape of the European 

 species. 



A feature worth special mention is the apparently vesicular expansion 

 of the nema. This has hitherto not been observed in any American species 

 of Diplograptus, though it is known to European paleontologists from 

 D. vesiculosus Nich. and D. appendiculatus (Tornq. ms) 

 em. Elles. 



Diplograptus longicaudatus sp. nov. 



Plate 16, figure 11 



Description. Rhabdosome small, attaining its full width (2 . 8 mm) near 

 the sicular end; The thecae are closely arranged (16 in 10 mm); inclined at 

 an angle of 35" to 40° ; in contact for about half their length ; their outer 

 margins strongly concave ; the apertural margins strongly convex ; the blunt 

 marginal angles turned downward. Virgula stout and long. Sicula not 

 observed. 



Position and locality. Extremely rare in the horizon with Diplo- 

 graptus dentatusat the Deep kill. 



Remarks. This species is based on a single specimen. This could in 

 some of its features, be called an extreme form of D. d e n t at u s, notably in 

 the possession of the long sicular, terminally filiform spine (virgella) and the 

 close arrangement of the thecae. It differs, however, too much from that 

 species in the character and inclination of its thecae to be safely identified 

 with it. 



