192 BULLETIN OF THE NATURAL HISTORY SOCIETY. 



Urotheca pervetus, n. sp. PI. I., fig. 8. 

 Only the distal end of this tube is known, and that pressed flat 

 in the stone so that the form of the orifice is not seen. Size — Length 

 of the part preserved 35 mm., width 3£ mm. ; rate of tapering, 1 in 

 17 mm. 



Helenia granulata, n. sp. PI. II., figs. 7, a to e. 



Small, much flattened, curved tubes, the curve not in one plane, 

 but the tube somewhat twisted. The tubes enlarge towards the 

 aperture so that in 10 mm. of the length the width is doubled. 

 Width of the orifice 2^ mm. Surface minutely granulated. 



The form and curve of the fragments of these tubes cause them 

 to resemble those of the genal and pleural spines of trilobites, but 

 we have found nothing resembling the cheeks or head of trilobites in 

 the bed where these fragments are found. 



Hyolithellus micans, Billings, (pars). PI. II., figs. 1., a to rf. 



These appear to be much smaller than the limit of size assigned by 

 Mr. Billings for his species. But I surmise that objects similar to 

 these have been included under his name. Size — The longest are 

 20 mm. with a width of 1 mm. The surface, though shining, is not 

 quite smooth, but is minutely granulated. These objects appear to be 

 clustered in the shale, as though they were gregarious, or were attach- 

 ments of larger organisms. 



Hyolithellus ( 1 ) flexuosus, n. sp. PI. I., fig. 9. 



A small slender tube of which the proximal end is very slender, 

 sti'aight and hyaline. This enlarges somewhat abruptly into a terete, 

 opaque tube, which is curved in one or more planes. Rate of taper of 

 the known part 1 in 20 mm. 



This species differs from Hyolithes Icevigatus, Linrs., (Torellella, 

 Holm.) in its circular form and calcareous substance. 



The slender, cylindrical, hyaline tube in which this species begins 

 was possibly membranaceous ; if chitinous it was extremely thin. 



Coleoides typicalis, Wale. PI. II., fig. 2. 



Objects which appear to agree in all respects with this species are 

 common with Hyolithellus, from which some can hardly be distin- 

 guished ; they have a length of 10 mm. and a width of 1^ mm. 



