PLATE XII. 



rio. 



1. — A spinous variety of EucjTtidiiun ampiillus (?) the narrow end 



prolonged into a tubiilous spine, — diam. of Ijulb, .00275. 



Chimborazo, Barbados. 



2. — ^Podocyrtis (?) whole height, .0112; breadth, 0055 ; height of cupola, 

 .0027. Professor J. Sliiller says " in aU the flask and beU-shaped 

 Polycystins, the first joint (glied) of the reticulation begins from 

 the top, and the number of the increasing links progresses with 

 growth in a definite ratio." The links of the lower part in this 

 fossil skeleton seem rimning into each other irregularly, like 

 dropped stitches in a stocking, or bursting bubbles in a gelati- 

 nous film while solidifying. 



3. — A further variation of Podocyrtis Schomburgkii, as shewn on 



plate I, fig. 3. 

 4. — A modificatiou of fig. 2, on plate I. 



6 & 6.- — Tlie reticulations progressing further towards the "iarfrfe/," 

 or Lattice-shape. In tig. 6, the inner net is very plainly seen, 

 its reticulations are also scpiare, with (juarter-inch magnifying 

 power used, about 470 linear. Springfield, Barbados. In ano- 

 ther slide is a broken-oft' top of one of these Ladder-Pyramids, 

 with the narrow neck swelling out into the surmounting ball 

 nucleus (?) 



