MEMOIRS OF THE NATIONAL ACADEMY OF SCIENCES. 



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Fio. 13 (a-c). 

 Mmilehm nirr-tata.-Figs. 13. Series of diagrammatic figures illustrating the mesenterial sequence in larvaj and larval polvps. a b arc taken 

 from H. V. AVilson'o (18S8) account of the development of this species, a. Stage with two pairs of protocnemes, one pair of which is 

 united witli the stomodwum {rf. Wilson's lig. l.s,. I, stage with three pairs of i>rotocnemes. two pairs united with the stomodioum (c/. 

 \\ils(jn s hg. 27). c. Stage with four pairs of protocnemes (c/. I'l. xix, fig. 134). <l. £c/icarrfsm-stage. The larva is now fixed and remains 

 at this stage for a considerable time, during which the six eiitocoelic septa are developed, and also the two cycles of tentacles (c/ 

 PI. XIX, fig. 135). e. Stage with six pairs of protocnemes, all united with the stomodseum, and the first cycle of metacnemes. 



