[81] The German abstract is very obscure as to the formation of the mouth.
[82] I have this on the authority of Kleinenberg. The existence of an unequal segmentation probably indicates an epibolic gastrula.
[83] “Ueb. einige tropische Larven-formen.” Zeit. f. wiss. Zool., vol. XVII. 1867.
[84] Chun (No. [174]) gives a short statement of his observations, which accords with the interpretation in the text.
[85] The questions relating to the generative organs of the Cœlenterata are dealt with in the second part of this work.
[86] The differentiation of the nervous and muscular systems in the Hydrozoa is treated of in the second part of this work.
[87] For a full account of this subject the reader is referred to the beautiful memoir of Allman (No. [149]).
[88] Vide also Moseley. Notes by a Naturalist of the Challenger, pp. 524 and 525.