PLATE VI. 
Halysites lithostrotonoides, Eth. fil. 
Fig. 1. Transverse section exhibiting the form of the fenestrules ; an incomplete chain; long 
regular autopores with narrow mesopores between them, and polygonal gonopores. — 
x 10. 
Fig. 2. Longitudinal section showing the visceral chambers and tabulae of autopores and 
mesopores, and those of a gonopore. The tube on the extreme upper right is a 
gonopore. — x 9. 
Halysites gamboolicus, Eth. fil. 
Fig 3. Transverse section exhibiting the form of the fenestrules ; length of the corallite chains ; 
long-oval autopores with thick walls, and septal-spines ; transversely elongate meso- 
pores, and polygonal gonopores. — x 9. 
Halysites australis, Eth. fil. 
Fig. 4. Longitudinal section exhibiting the autopores with numerous cut septal spines, and 
narrow pipe-like mesopores. — x 8. The specimen from which this section is prepared 
is in a highly altered condition ; a far better illustration will be found in PI. VII, 
Fig. 6. 
Halysites cratus, Eth. fil. 
Fig. 5. Transverse section showing the labyrinthine fenestrules ; strongly farcimentiform coral- 
lite chains ; large oval autopores ; and large mesopores in marked re-entrant spaces. — 
x 8. 
Fig. 6. Longitudinal section exhibiting the visceral chambers and regular horizontal tabulae of 
the autopores ; distant tabulae of the mesopores, and those of a gonopore on the extreme 
right, between two autcpores, — x 8, 
