PLATE IX. 



ACTINOCERAS PROPINQUOM, sp. nOV. 



Figs. 1 a, 1 b. Fragment of the septate part of the shell, imperfect at both 

 ends ; the test has been removed and the under surface polished to show the 

 septa ; the apical part, 1 c, 1 d, is cut longitudinally to show the siphuncle and the 

 endosiphuncle within. 1 b is separated from 1 a on the plate to enable the 

 specimen to be figured without reducing its size. 1 e. Transverse section 

 showing the siphuncle. Little Island. Dublin Museum of Science and Art. 

 (Page 33.) 



ACTINOCERAS GIGANTEUM, J. HowerblJ. 



Fig. 2 a. Longitudinal section of a fragment, showing si, the endosiphuncle, 

 with remains of the tubuli, t, t, given off from it. 2 b. Longitudinal section of 

 another fragment, showing at n, n, the necks of the septa. No remains of the 

 endosiphuncle are preserved in this specimen, which is filled with crystalline calcite. 

 2 c. Fragment with casts of the bulbous siphuncular segments ; one of them 

 shows the puckered appearance characteristic of their calcareo-membranous walls. 

 Castle Bspie Museum of Trinity College, Dublin. (Page 28.) 



