172 ZOOPHYTES. 



Plate XXXVIII. Fig. 6. System consisting of five ascidise in regular arrange- 

 ment. 



7. System of six ascidise. 



8. System of six ascidise. 



9 . System composed of a number of ascidise in irregular 



arrangement. 



10. System composed of a number of ascidise in irregular 



arrangement. 



11. System composed of a number of ascidise in irregular 



arrangement. 



1 2. System composed of nine ascidise in elliptical arrange- 



ment. 



13. System composed of ten ascidise in elliptical arrange- 



ment. 



14. System composed of ten ascidise nearly in circular 



arrangement. 



15. System of ten ascidise in elliptical arrangement. 



16. System consisting of a double row, exterior and inte- 



rior, each row with a number of ascidise in elliptical 

 arrangement. 



All the figures of this Plate, except the first, are 

 enlarged. 



Plate XXXIX. Fig 1. Botryllus in an early stage, spreading on a leaf, April 11. 



2. The same April 18. Diffusing margin a, b. 



3. The same May 24. The ascidise now arranged in defi- 



nite systems. Lowest system of nine ascidise c. 



4. The lowest system c, of fig. 3, magnified. 



5. Portion of the diffusing extremity a, b, of fig. 2, as on 



April 18, shewing part of the sanguiferous system. 

 6, 7, 8, 9. Different systems of ascidise of the Botryllus. 



All the figures of this Plate, except fig. 1, are enlarged. 



Plate XL. Fig. I. Botryllus of triangular form, and yellow colour. 



2. System of the same. 



3. The same system enlarged. 



4. Botryllus consisting of a superficial patch of irregular systems. 



5. System of fig 4, enlarged. 



