PLATE XVIII. 



Fig. 603. Chaetoceros armatum, West, p. 421. 



Fig. 604. Cha-toceros Wighamii, Brightw., p. 422. 



?- g ' ^o' Chaetoceros (Baeteriastrum), varians, Lauder, p. 422 



Xig. 608. Melosira nummuloides (Bory), A. p 440 



Fig. 609. Melosira Westii, Wm. Sm., p. 441.' 



Fig. 610. Melosira Borreri, Grev., p. 441. 



Fig-. 611. Melosira varians, Ag., p. 441. 



Fig. 612. Melosira Jurgensii, Ag., p. 442. 



Fig. 613. Melosira Jurgensii, var. octogona, Grun., p. 442. 



