MEM. M. C. Z., IX. No. 3. — ACALEPHS, POLYPS. 45 



35, 36. Edioardsia? (Kallipliohe aj^jmuUculata'BnuiAx.) From "VVilhelm Busch, Beobachtungcn iiber Anatoiiiie, 

 etc. (cited above), pp. 130-132, Taf. XIV. figs. 8, 10. Magnified about 100 diam. 



35. Laiva with oral end down. Into the general cavity two club-.shaped organs (hi nl. fil. ?) project. At tlie aboral 



pole there is a tuft of cilia, half as long as the body, which is only partially represented in this figure. 



36. The same larva as that last figured with the club-shaped organs protruded through the mouth. The latter are 



ciliate, and armed with nettle-cells like the ectoderm. 



ST-IS. Alcyonium digitatum Lam. From A. O. Kowalevskj', Observations on the Development of Ccelenterata 

 (cited above), pp. 16-23. Taf. IV 13. and V. 



Note. — Tlove of the earliest stages are figured at the bottom of Plate XII. figs. 57-59. 



37. The central, as well as the outer, layer has broken up into nucleated cells. 



38. The larva is already formed. The limits of tlie inner cells and their nuclei are only very indistinctly visible. 



39. (Fjrroneonsly numbered 30.) An advanced stage of a free swimming larva. The cutodcrmic cavity is nearly 



filled with yolk substance (vt.), containing at one pole transparent vacuoles. 



40. A larva whicli has become attached. 



41. Around the infolding which was formed at the upper end there have grown out eight rounded protuber- 



ances. 



42. A cross section of the preceding stage, showing the pharyngeal sac (phx.), the continuous layer of sub-rcto- 



dermic cells, — the middle layer {tasd.), — and the walls of the mesenteries surrounding still persistent 

 masses of yolk. 



43. Cross section of a more .advanced stage than the preceding. The remnant of the yolk (vt.) lines the inner 



surface of the entoderm, and tlie mesoderm (msd.) is composed of a double layer of spindle-shaped cells. 

 The membraua propria is seen between the entodermic walls of the mesenteries. 



