EXPLANATIONS OF PLATE XVIII. 
DENDROGRAPTUS? (CALLOGRAPTUS ?) DIFFUSUS, page 132. 
Fig. 1. A portion of a broken frond from near the base. The test is removed in some 
parts, showing celluliferous markings. 
2. A fragment of another specimen with similar cell-markings. 
“ 3. An enlargement, showing the cell-apertures. The specimens are extremely 
compressed. 
CALLOGRAPTUS ELEGANS, page 134. 
Fig. 4. A fragment which is more lax and spreading, with shorter branchlets 
than the ordinary specimens, but having similar strie, and a similar arrange- 
ment of cellules. 
DENDROGRAPTUS GRACILIS, page 132. 
Fig. 5. Two of the larger branches with their sub-divisions, of the natural size. 
‘ 6. An enlargement from one of the branchlets, showing the striate surface and 
the deep indentation of the cellules. 
