98 PROCEEDINGS OF THE NATIONAL MUSEUM 



VOL. 78 



We have no new observations to add to the description of this 

 species save the remarks as to the classification of the genus given 

 above. Lepiditta alata, Modioloides prisca, and the present species 

 seem to us related but in each case more material for study is needed. 



Occurrence. — Lower Cambrian, Troy, New York. 



Genus MODIOLOIDES Walcott 



Modioloides Walcott, Amer. Journ. Sci., ser. 3, vol. 38, 1889, p. 29. 



The single specimen representing the genotj^pe and only species of 

 this genus is the cast of a valve which on account of the presence of a 

 muscular scar at the anterior end just \\'ithin a supposed pallial hne 

 caused its reference to the pelecypoda. The shell structure is cal- 

 careo-phosphatic as in Fordilla and allied genera, so that Modioloides 

 is very probably a crustacean best referred, with present knowledge, 

 to the Limnadiidae. 



Genotype. — Modiolopsis? prisca Walcott. Lower Cambrian. 



MODIOLOmES PRISCA (Walcott) 



Plate 4, Figure 16 



Modiolopsis? prisca Walcott, Amer. Journ. Sci. Arts, scr. 3, vol. 34, 1887, p. 191, 



pi. 1, fig. 19. 

 Modioloides prisca Walcott, Tenth Ann. Rep. U. S. Geol. Surv., 1890, p. 615, 



pi. 73, fig. 3. 



Our unretouched photograph of the type specimen indicates that 

 the oval muscle scar at the supposed anterior end is possibly due to a 

 crushing of the test, a condition very commonly found in the Cam- 

 brian Conchostraca. At any rate, more material is necessary before 

 the relations of this interesting fossil can be established. 



Occurrence. — Lower Cambrian; Whitehall, Washington County, 

 N. Y. 



SPECIES OF UNCERTAIN AFFINITIES 



ENTOMIDELLA(?) BUPRESTIS (Salter) 



Plate 8, Figures 20, 21 



Leperdiiia buprestis Salter, British Ass. Rep., Trans. Sec, 1865, p. 285. 

 Entomis buprestis Jones, Quart. Journ. Geol. Soc. London, vol. 28, 1872, p. 183, 



pi. 5, fig. 15. 

 Entomidella buprestis Jones, Ann. and Mag. Nat. Hist., ser. 4, vol. 11, 1873, p. 417 

 Leperdiiia punctatissima Sulti, Siluria, app. 1865, p. 519. 



Remarks. — This peculiar species apparent!}'^ is known as j'^et only 

 from the specimen originally described by Salter. A photographic 

 reproduction of Jones's figure of this specimen is given on Plate 8 

 The descriptive remarks published by Salter and later by Jones are 

 in both instances exceedingly unsatisfactory. The valves are repre- 

 sented as "very elongate ovate" but their borders are said to be 

 -'partly embedded" in the matrix: and the surface of the "pyritous 



