EXPLANATION OF PLATE XXXVIL 

 Fig. 



1-8. ZOOTHAMNIUM ARBUSCULA, Ehr., vol. ii. p. 694.— I, Fully extended adult colony- 

 stock with at a a large subspheroidal reproductive zooids, X 100; 2, a similar 

 colony-stock, natural size ; 3, colony-stock in a semi-contracted state ; 4, 

 isolated conical zooid, x 350 ; S, spheroidal reproductive zooid, as delineated 

 by H. E. Forrest ; 6 and 7, successive phases of growth of a reattached repro- 

 ductive zooid ; 8, ordinaiy conical zooid with the anterior border plicately 

 contracted. 



9-12. ZOOTHAMNIUM DICHOTOMUM, Wright, vol. ii. p. 697. — 9, Adult colony-stock, 

 X 50 ; 10, an isolated zooid, x 200; 11, colony-stock in semi-contracted 

 state; 12, scarcer reproductive zooids, x 200. 



13, 14. ZOOTHAMXIUM NIVEUM, Ehr., vol. ii. p. 694. — 13, Adult colony-stock, x 50; 

 14, isolated zooid, x 200. 



15. ZOOTHAMNIUM ClENKOWSKll, Wrz., vol. ii. p. 696, X 400 (Wrzesniowski). 



16. ZOOTHAMNIUM PAR.\SITA, Stein, vol. ii. p. 69S, X 100 (Stein). 



17-19. ZOOTHAMNIUM CARCINI, S. K., vol. ii. p. 700.— 17, Adult colony-stock, x So ; 

 18 and 19, expanded and contracted zooids, x 200. 



20-24. ZOOTHAMNIUM ALTERNANS, C. & L., vol. ii. p.695.— 20, Adult colony-stock with 

 various sized zooids, as delineated by Greefif, x 125; 21, attenuate undeveloped 

 colony-stock, as observed by the author ; 22 and 23, larger reproductive zooids 

 with subcentrally developed supplementary ciliary girdles ; 24, portion of 

 pedicle with finely striate central cord, as observed by the author ; 25, a 

 portion of the same structure, as delineated by H. E. Forrest. 



