CORRECTIONS.* 



P. 7, line 5. — For lumen is, read lamina are. 



P. 9, line 18. — For oval, read oral. 



P. 12, line 32. —For Fig. 5, read Figs. 8, 10 and 11. 



P. 14, line 20. — For Plate II. fig. 2, 3, 5, read Plate II. fig. 3. 



P. 34, line 28. — For Maccoy, read M'Coy. 



p. 47, line 22. — For Codastus, read Codaster. 



footnote. — For ralated, read related. 

 P. 49, line 10. — For impossible, read impossible. 

 P. 51, lines 13, 15. — For Canedayi, read Cassedayi. 

 P. 53, line 22. — For ambulacria, read ambulacra. 

 P. 55, line 18. — For plicable, read plicated. 



line 35. — For prominent, read promising. 

 P. 59, line 18. — Omit comma. 

 Explanation of Plate II. No. 5. — Add, enlarged four times. 



No. 11. — Add, in a Codaster. 

 Explanation of Plate IV. No. 6. — For pyramidalis, read bipyra- 



midalis. 

 P. 69, line 18. — The equation should read S= a-}- 6e-^'* 

 P. 72, line 5. — For 13.5, read 19.95. 

 P. 147, equation (12). — For (2 — n), read (2 — n)^- 

 P. 155, line 3. —For 2C, read 2Cp. 

 last line. — For aT, read clT. 

 P. 156, equation (17)'. — For ilf — , read iiyr=. 



P. 157. — For W= 4 tt f E^ Pd R, read W= Air C R^PdR. 



^ ^ R 



P. 160, equation (41) and preceding equation. — For Cp , read Cp. 



(8— 5n) (4 — 3n) G 

 P. 163, equation (50). - Read, S = ^^g^^^^^W^^ J ' 



Q 



following equation. — Read = 0.177 y • 

 P. 181, line 21. — For Hall, read Hale. 



* Some of these changes require to be made in only the latter part of the 

 edition, from which type appears to have fallen. 



