E. B. Cumings — Development of Fenestella. Ill 



Figure 30. — Protoecium, ancestrula, and primary bud of Tubulipora. After 



Barrois. x 27. 

 Figure 31. — Same ; seen from the under surface, x 27. 

 Figure 32. — Ancestrula and primary bud of Schizoporella. x 33. 

 Figure 33. — Protoecium and primary zooecia of Phylloporina corticosa from 



Cannon Falls, Minnesota, x 17. 

 Figure 34. — Protoecium of Polypora from the Lower Helderberg of Indian 



Ladder, New York, x 28. 

 Figure 35. — Protoecium of Thamniscus from the Upper Coal Measures of 



Kansas, x 17. 



Plate VII. 



Figure 36. — Longitudinal section of Fenestella, in the plane of /-/, figure 

 48. x 17. 



Figure 37. — Longitudinal section in the plane of g-g, figure 48. x 17. 



Figure 38. — Longitudinal section in the plane of h-h, figure 48. This sec- 

 tion shows remarkably well the shape of the nepiastic zooecia. x 17. 



Figure 39. — Longitudinal section in the plane of i-i, figure 48. x 17. 



Figure 40. — Transverse section in the plane of a-a, figure 47. Shows the 

 primary buds {2, 3). x 17. 



Figure 41. — Transverse section of another specimen in which the primary 

 and secondary buds have a rather unusual arrangement, x 17. 



Figure 42. — Transverse section in the plane of a' -a', figure 47 (cf. fig. 5). 

 Same specimen as figures 54-58. x 17. 



Figure 43. — Transverse section in the plane of 6-6, figure 47. Shows the 

 proximal end of the tertiary bud (cf . fig. 10). x'17. 



Figure 44. — Probable interpretation of figure 39. Section in the plane of 

 i-i, figure 48. * 



Figure 45. — Semidiagrammatic drawing of a longitudinal section (in the plane 

 of j-j, fig. 48) of a specimen showing the ancestrula and two zooecia, 

 probably one of the secondary buds and a tertiary bud (17, III), x 17. 



Figure 46. — Semidiagrammatic drawing of a longitudinal section (in the 

 plane of k-k, fig. 48) of the ancestrula and protoecium of another speci- 

 men, x 17. 



Figure 47. — Semidiagrammatic drawing from figure 37, to show the position 

 of transverse sections. 



Figure 48. — Semidiagrammatic drawing from figure 43, to show the position 

 of longitudinal sections. 



Figure 49. — Ephebastic zooecia of Fenestella. Specimen from Thedford, 

 Ontario. x 17. 



Figure 50. — Nepiastic zocecium of Fenestella. Specimen from Thedford, 

 Ontario, x 17. 



Figure 51. — Neanastic zooecia of Fenestella. From the proximal portion of 

 the cone of the same specimen as that shown in figure 38. x 17. 



Figure 52. — Ephebastic zooecia of Fenestella acmea from the Waldron shale 

 of Tarr Hole, Indiana (cf. fig. 51). x 17. 



Figure 53. — Ephebastic zooecia of Protocrisina exigua Ulr. from the Tren- 

 ton limestone of Montreal, Canada (cf. fig. 50). Alter Ulrich. x 18. 



Figures 54-^8. — Serial sections of a Fenestella base. Same specimen as 

 that shovvn in figure 42, figure 54 being the next section above. Fig- 

 ures 55-58 are successively higher sections, x 17. 



Figure 59. — Longitudinal section (in the plane of j-j, fig. 48) of a Fenestella 

 base, showing the shape of the ancestrula most often seen, and three 

 nepiastic zooecia (II, III, z"). x 17. 



Figure 60. — Semidiagrammatic drawing from figure 59. 



