PLATE IV. 



Fig. 1. ZAPHRENTIS PENESTEATA, Nich. Nat. size. (p. 22.) 



Fig. 2. BLOTHROPHYLLUM APPROXIMATUM, Nich. Nat size. (p. 19.) The epitheca has 

 been decorticated. 



Fig. 3. BLOTHROPHYLLUM DECORTICATUM, Billings. A fragment from which the epitheca 

 has been removed. Nat. size. (p. 19.) 



Fig. 4. CLISIOPHYLLUM ONEIDAENSE, Billings. A small example from which the 

 epitheca has been removed. Nat. size. (p. 20.) 



Fig. 5. Another specimen of the same, in which the epitheca is also wanting. 



