ERRATA. 



Page 93, line 17 from bottom, for " Athyris" read " Meristella." 



Page 99, line 18 from bottom, for figure 18 " read " figure 17." 



Plate II. figure 2. Cladopora vertidllata. The engraver has omitted the " a " which should stand at the upper 

 left hand side at the semicircular notch. 



Plate II. figure 15. Oonocardium ornatum. The engraver has omitted the delicate radiating lines on the ante- 

 rior side, and the delicate concentric lines of the rostrate side. 



Plate III. figure 3. Clidophorus Me Chesneyanus. The muscular impression has been omitted in the engraving. 



Plate III. figure 11. Lichas decipiens. The outline is palpably incorrect. Moreover, the lines separating the 

 articulations of the lateral lobes do not exhibit the curvatures noticed in the description. 



Plate III. figure 13. Acidaspis Ida. The engraver has omitted the furrow behind the ocular filet or thread on 

 the right side. 



