308 CRETACEOUS PALEONTOLOGY. 



Serpula whitfieldi n. sp. 



Plate XIX., Fig. 2. 



1892. Diploconcha (Serpula?} cretacea ? Whitf., Pal. N. J., 

 vol. 2, (Monog. U. S. G. $., vol. 18), p. 170, pi. 20, 

 fig. 25. (Not Diploconcha. cretacea Con.) 



Description. Tubes irregularly arcuate, slightly flexuose, in- 

 creasing in diameter very gradually; surface of shell lamellose 

 where partially exfoliated, in cross-section appearing to be made 

 up of concentric lamellae. 



The dimensions of the largest tube observed are : total length, 

 70 mm., maximum diameter, 6.5 mm. 



Remarks. The type specimen consists of several more or less 

 complete calcareous tubes which are attached to the surface or 

 penetrate the substance of some thick pelecypod shell. The two 

 largest tubes, the ones illustrated by Whitfield, lie in a position 

 essentially parallel with one another, and besides these there is 

 another apparent pair of smaller tubes upon another surface of 

 the specimen. Because of their apparent occurrence in pairs, 

 Whitfield identified this specimen with Diploconcha cretacea 

 Con., but they differ from that species -in not having the tubes 

 in contact in any portion of the specimen as preserved, and in 

 having a rather heavy and thick shell. This apparent occurrence 

 in pairs, however, is probably accidental rather than funda- 

 mental, since other individuals are present upon the specimen 

 which give no evidence of being in pairs, although it must be 

 said that the unpaired individuals are less complete than those 

 in pairs. The tubes have much the appearance of the tubes of 

 Teredo, but no evidence of the presence of a bivalve shell has 

 been seen. 



Formation and locality. Navesink marl, Crosswicks Creek 

 (Whitfield). 



Geographic distribution. New Jersey. 



Serpula rotula (Morton). 



Plate XIX., Figs. 8-10. 

 1834. Vermetus rotula Morton, Synop. Org. Rem. Cret. Gr, 



U. S., p. 81, pi. i, fig. 14. 

 1861. Spirorbis rotula Gabb, Synop. Moll. Cret. Form., p. 148, 



