EXPLANATION OF THE PLATES. 
589 
the furrowed surface of the terminal portion of the radiating prolongations. 
Magnified 40 diameters. 
Figs. 7, 8, 9, 10. Specimens of the Philippine variety of Tinoporus haculatus^ showing 
the variability of their form. Magnified 12 diameters. 
Pig. 11. Fragment of Polystomella craticulata, showing the furrowed internal surface of 
three of the chambers, a, the furrows being deepest at the posterior 
margin for the reception of the retral processes ; whilst at hlf, are shown 
two of the meridional canals laid open by the fracture of the septa which 
contained them, with the series of orifices of the diverging canals which pass 
off beneath the ridges that intervene between those furrows. Magnified 40 
diameters. 
Fig. 12. Internal cast of the chambers and canals of Polystomella craticulata, repre- 
senting the form of the body and the distribution of the canal-system: 
«, retral processes, proceeding from the posterior margin of one of the 
segments ; h b', smooth anterior margin of the same segment ; c, c', stolons 
connecting successive segments, and uniting themselves with the diverging 
canals*; d, d\ d^, three turns of one of the spiral canals; e, e\ three 
of the meridional canals ; f, f\ /*, their diverging branches. Magnified 40 
diameters. 
Fig. 13. Fragment of a similar cast, showing a portion of three segments on their 
internal aspect, with their connecting stolons, c, two of the meridional canals, 
ed, and their diverging branches jf,/*. Magnified 40 diameters. 
PLATE XIX. 
All the figures in this Plate refer to Calcarina Sjjengleri. 
Fig. 1. Disk of Philippine variety, as seen on the side nearest the apex of the spire, with 
the origins of the spines; showing the minute punctations and scattered 
tubercles of the surface of the disk, and the furrowed surface of the spines; 
the spire not anywhere apparent. Magnified 20 diameters. 
Fig. 2. Disk of Maltese variety, as seen on the same side, showing the entire length 
of the spines, which in this specimen are unusually numerous and tend to 
subdivide at their extremities; no markings of any kind are seen on its 
surface, nor is the spire in the least apparent. Magnified 20 diameters. 
Fig. 3. Disk of Philippine variety, as seen on the same side, with the origins of the 
spines, showing the punctations of the disk and the furrowing of the spines, 
with an unusual abundance of semitransparent tubercles ; the spire not any- 
where apparent. Magnified 20 diameters. 
* This portion of the figure is ideal ; and by a misapprehension on the part of the artist, the segments 
of the inner whorl have been made to range with those of the outer whorl, instead of alternating with tliem 
which seems to be the typical arrangement, though often departed from. 
