BUIIY'S FIGURES OF POLYCYSTIN^. 



PLATE I. 



riG. 



1 & 6. — Varieties of Eucyrtidium Acuminatum of Ehren- 



berg. 

 5. — Podooyrtis Schombuvgkii. Ehrenberg. 

 2, 3, 4. — Varieties of the same. 



4.— 



5.— 

 6.— 



PLATE II. 



■ Stylodictya Gracilis. Ehrenberg- 



■ A Dictyospiris (?) of Ehrenberg, highly developed in 



in slide Zjg Cambridge, Barbados. 



■ Dictyospiris (?) or perhaps Petalospiris (?) May they 



not possibly be the same organisms in different states 

 of development ? Ceratospiris, Mikrogeologie, PI. 

 XXII, fig. 37, also resembles these shapes which 

 occur in great variety in the Barbados deposits. 



Ehabdolithes Pipa. spiued stem var. Ehrenberg places 

 Rhabdolithes in the family of Geolithen. 



Stephanolithes Nodosa. ; also a Geolithen of Ehrenberg. 



Acanthodesmia of J. Miillcr (Mittelmeeres, p. 30) Ste- 

 phanolithes Spinesoens (?) of Ehrenberg. It occurs 

 in double and single circlets, and with varying num- 

 ber of spines in the Barbados deposits. 



2.— 



3.- 



4. 



PLATE III. 



A Polycystinous nucleus, with one spine running through 

 it, and attached at each end to a plain circle of Silex. 

 — (In shde B. VI. Cambridge, Barbados) Lithocircus, 

 Mesocena (?) 



A similar nucleus with four Acanthometrum shaped 

 spines (see Miiller's Mittelmeeres, &c., PI. X.) attached 

 to it, the hooks of which describe part of a circle. 

 Actiniscus (?) in slide T. Cambridge, Barbado.i. 



A Hyaline wand, spirally twisted. 



Rhabdolithes Pipa. var. Ehrenberg. 



1.- 

 2_. 



3. 

 4.- 

 5. 

 6. 



PLATE IV. 



• Stephanastrum. Ehrenberg. 



• Astromma Aristoteles. Ehrenberg. 



■ Stylosphiera. Ehrenberg. 

 -Haliomma with four spines. 



- Lychnocaniuni falciferum. Ehrenberg. 



■ Stylosphsera var. (?) with outer web (?) 



PLATE V. 



■ Astromma (?) finely developed with part of outer web 



adhering between the arms. 

 - Eucyrtidium Mongolfieri. Ehrenberg. 



3. — Podocyrtis Mitra. Ehrenberg. 



4. — A state of Rhopalocanium (?) 



5. — Ptcrocodon Campana. Ehrenberg. 



6. — an Astromma partially developed (?) 



PLATE VI. 



1, 2, 3, 4, 5.— Rhopalocanium Ornatum in dift'erent states. 

 6.— Spicule of (?) 



PLATE VII. 



1 & 2.— Surirella (?) from Cambridge, Barbados. Fig. 1 pos- 

 sibly a young, less developed, form of fig. 2. The 

 slide from which the fig. 2 was drawn was returned to 

 Mr. Johnson, and by him sent to Mr. Ralfs, Pro- 

 fessor W. C. Williamson saw it when in Mrs. Bury's 

 hands (October, 1860), and kindly suggested it might 

 possibly be a Surirella. 



3 & 4.— Varieties of Dictyospiris (?) Ehrenberg. 



5.— Actiniscus (?) of Ehrenberg and Pritchard ; a triangular 

 net, like a Dictyocha, but with a " solid centre," which 

 centre (or nucleus) gives the idea of being capable of 

 stretching up into a Podooyrtis-like form ; sides of 

 triangle measure .006.5 ; there are nine outer and six 

 inner cells, arranged round a solid-lobed and punc- 

 tured nucleus, which bears one long and two short 

 spines. 



6:— A Desmidia-like, but silicious, clear, transparent plate, 

 with waved edges, and a perforated centre. Appears 

 to resemble, in some degree, Lithodesmium undulatum, 

 of Ehrenberg's " Kreidebildung," page 76. Dr. 

 Wallich suggested (from sketch) that it might be a 

 part only of some polycystinous form. 



7. — The upper part like Ehrenberg's Podocyrtis Cothurnata, 

 but with a tubulous prolongation of the base. 



1,2, 



PLATE VIII. 



3^ & 4. — Varieties of Haliomma. Haliomma Hum- 

 boldtii (?) of Ehrenberg, from Cambridge, Barbados, 

 numerous and variable. Although there are some- 

 times indications of spines radiating from the centre, 

 as in Stylodictya, yet the points round the edge 

 appear to be merely "marginal appendages." — Dia- 

 meters, including spines, from .0077 to .0085. 



6. — Muller describes these as stages of growth of the 

 Haliomma, where the outer web is spinning itself 

 over and round the central nucleus, and the siliceous 

 rafters or supports extending like a framework from 

 the nucleus to the exterior covering. Page 21 ';' 

 " Thalassicollen Polycystinen, &c., des Mittelmeeres." 

 & 8. — Spines or Spicules in Barbados deposit. 



5, & 



