PLATE XXXII.— Continued. 
Hyolithes aclis. 
Page 197. 
Fig. 22. The ventral side of a large specimen fractured by compression. 
Fig. 23. The opposite side of the same. 
Fig. 24. Profile outline of the same, showing the convexity. 
Fig. 25. A more expanded and comparatively shorter form. The cavity contains the head of a small Dal- 
manites. 
Fig. 26. A transverse, section of a specimen of this species. 
Figs. 27, 28. Two different forms of operculum associated with the above, and supposed to belong to the 
same species. 
Fig. 29. An enlarged figure from a specimen of angular form, showing obscure longitudinal strise, and distinct 
suture-like lines. In the Illustrations of Devonian Fossils this figure (as fig. 9 of Plate XXVII) 
is erroneonsly referred to H. striatus. 
Hyolithes aclis, var. petaloidea. 
Page 197. 
Fig. 30. The ventral side, with the central portion depressed, and limited by a distinct angularity on each 
side. 
Hyolithes striatus. 
Page 199. 
Fig. 31. An enlargement of a specimen to three diameters, showing the ventral surface with longitudinal 
stride, and the impression of the angular side with characteristic impressed lines. 
Fig. 32. An enlargement of the dorsal surface to Six diameters, showing the longitudinal strife. 
Fig. 33. A transverse section of a specimen of this species. 
Fig. 34. An operculum found associated with the specimens, and supposed, from its form and radiating 
strise, to belong to the species. 
