PLATE 87. 
Riga: 376. 1. TuHeca? TRIANGULARIS. (Pag. 313.) 
1 a. A portion of a large specimen, with the smaller extremity broken off. 1c. Section of the same. 
1b. A smaller specimen, very perfectly terminated at both extremities. 
1d. A minute specimen of the same species. 
Fig. 2. 375. 2. ORMOCERAS CREBRISEPTUM. (Pag. 313.) 
2a. A part of the outer chamber of this species. 
26. A fragment still preserving a portion of the shell, showing some strong longitudinal strie, and the dorsal 
line or ridge. 
2c. A fragment showing the position of the siphuncle on the highly arched septum at the upper extremity of 
the figure. 
2d. A fragment of stone, with numerous small specimens of this species, associated with crinoidal joints. 
2e. A longitudinal section of a fragment, showing the deeply arched septa, and the alternate enlargement and 
contraction of the siphuncle. 
+s These figures are all erroneously marked 4 on the plate. 
