L. Roule, Bull. Mus. Océanogr. Monaco, 1904, p. 3.
E. van Beneden, Les Anthozoaires de la Plankton Expédition, Kiel, 1898.
A. W. Peters, Journ. Exper. Zool. ii. (1) 1905, p. 103.
Cnidoblasts are stated by Chun to occur on the tentacles of Euchlora; and batteries of "nettle cells" by Abbott on the tentacles of Coeloplana.
The two costae that are seen in the middle when the Ctenophore is viewed in the transverse plane, as in Figs. 180 and 181, and the corresponding costae on the opposite side are called the "transverse" costae; the other four are called the "sagittal" costae.