DOUBTFUL SPECIES. 179 



figures, and come from the same locality as the type-specimen, it is very distinctly 

 a polyzoon belonging either to Hippothoa or Stomatopora. H. M. Fischer has 

 also stated that it belongs to the Bryozoa (" Recherches sur les Eponges perforantes 

 Fossiles," * Nouv. Archiv. du Mus d'Histoire Naturelle,' 1868, p. 133) . In Morris's 

 ' Catalogue,' 1854, p. 27, it is placed with the Amorphozoa under the genus Gliona. 

 The original specimens are from strata of Caradoc age, at Desertcraight, 

 Tyrone. 



58. Favospongia Ruthveni, Salter (MS.). 



1855. Brit. Pal. Fossils, pi. id, figs. 9, 9 a. 



The examples of this species are mere structureless casts of ovoid bodies, their 

 surfaces are covered with indistinct, circular, or irregular depressions. Their true 

 character is problematical ; there is no evidence to connect them with Sponges. 



The specimens thus named are from Upper-Ludlow strata at Benson Knot, 

 near Kendal ; they are now in the Museum of the Geological Society of London, 

 and in the Jermyn Street Museum. 



59. Ischadites microfora, Salter. 



1873. Cat. Cambrian and Silur. Foss. Cambridge, p. 40. 



The specimen thus named is a fragmentary cast of some organism exhibiting 

 rows of puncta on the surface of compressed shale. It does not show any resem- 

 blance to Ischadites or allied forms. The original, now in the Woodwardian 

 Museum at Cambridge, comes from Middle-Bala strata at Blaen-y-cwm, North 

 Wales. 



60. Mammtllopora mammillaris, King. 



1850. Mon. Permian Foss., Pal. Soc, vol. iv, p. 12, pi. ii, figs. 3, 4. 



The type is a small rounded mass with mammillary elevations. The surface is 

 entirely covered with very minute polygonal perforations, similar to those of the 

 doubtful organism Solenopora compacta, Billings sp. (see * Greol. Mag.,' dec. iii, 

 vol. ii, p. 529). No other structure is shown. This is certainly not a Sponge. 



From shelly limestone (Permian), Humbleton Hill. The type is in the Museum 

 of Queen's College, Galway. 



