140 Prof. Bailey on some new Fossil Infusoria. 



7. Dictyocha aculeata? (fig. 17.) Our figure represents a fos- 

 sil species of Dictyocha from Piscataway, which perhaps belongs 

 to Ehrenberg's species D. aculeata, for which he gives the fol- 

 lowing characters. " Cells arranged by sixes in the form of a 

 ring, each cell being spiny within." 



In figures 18, 19 and 20, are shown several other fossil species 

 of Dictyocha from Petersburg and Piscataway ; some of them are 

 probably new. 



In figure 21 is represented a fragment of a singular body, which 

 was rounded or pyriform, with large perforations in its surface. 

 Several fragments of similar bodies were found among the infu- 

 soria from Piscataway ; and in Plate III, figs. 27 and 28, of my 

 memoir on the Bacillaria, I have represented analogous bodies 

 from Richmond. Their nature is unknown to me. 



In figure 22 are shown small globular bodies, with projecting 

 spines, which occur fossil at Piscataway. They resemble some- 

 what the curious siliceous spiculee discovered by Bowerbank in 

 the Tethea lyncurium. 



Figures 23 and 23 b. show two other singular shaped spiculae 

 from Piscataway. 



Figures 24 to 27 show anomalous bodies occurring fossil at 

 Petersburg and Piscataway. They consist of an elliptical base, 

 supporting one or two conical bodies which terminate in simple 

 or branched projections. 



Figure 28 appears to be half of a body allied to Coscinodiscus, 

 but with radiating strise instead of cells upon its surface. Fossil 

 at Piscataway. 



Figures 29, 30 and 31, represent hollow glass-like siliceous 

 spines, not uncommon at Piscataway, but of whose nature I am 

 ignorant. 



None of our infusorial marls that I have yet examined contain 

 any Polythalamia, but in the accompanying tertiary beds of 

 shells, I have found numerous and highly interesting Polythala- 

 mian forms, which I propose to describe in a paper which I am 

 preparing upon the American fossil Polythalamia. All the fig- 

 ures which accompany this paper were traced from nature by 

 the aid of a camera lucida eye-piece, and are therefore correct as 

 far as they go, but all the minute markings are omitted. The 

 scale to which they are all drawn is shown in fig. 32, which 



