584 MR. E. A. MINCHIN ON THE ATTACHMENT _ [Nov. 19, 
capsules, such as are represented in figures 3, 4, and 5, the walls 
are relatively thick, containing a great deal of mesogloea, and the 
capsules themselves open by a comparatively wide opening into the 
lumen of the groove. In the larger capsules, on the other hand 
(figure 6), the mesogleea is scarcely visible, appearing as if squeezed 
out by the pressure of the numerous embryos contained in the 
capsules, and their openings are much narrowed. They always 
contain embryos in all stages of development, from segmenting ova to 
fully-formed planulz. In the series of sections from which figures 3, 
4, and 5 were drawn, several ova were found of only four or eight 
segments. In addition to the embryos contained in the brood- 
capsules, a great number are always to be found free in the bottom 
of the groove or lodged in the foldings of its margin. 
My excuse for publishing these details is that after I had made 
out the structure of the pouches from my sections, I consulted the 
numerous works on the anatomy and embryology of Aurelia, and 
found the brood-capsules quite erroneously described by Claus and 
Agassiz ; while in other writers I have found no mention of them 
at all. 
Claus (‘ Untersuchungen tiber die Organisation und Entwicklung 
der Medusen,’ Prag, 1883) writes :—‘ The ova pass from the ovary 
into the gastric cavity and through the mouth between the apposed 
surfaces of the arms, where, surrounded by a slimy excretory 
product of the endoderm (yon einer schleimigen Absonderungs- 
masse des Entoderms umbiillt), they run through their embryonic 
development up to the swarming planula, as if in a brood-cavity.”” I 
find this account to be incorrect, as far as my specimens go. 
Agassiz (‘Contributions to the Natural History of the United 
States,’ vol. iv.) states (pp. 14 and 15) that the embryos of Aurelia 
flavidula leave the ovary as small ciliated larve, either globular or 
oval in shape, and with distinct inner and outer walls‘; in this 
condition they reach the pouches. In another passage (p. 58) he 
says :—“ The ovaries ... . discharge their eggs into the cavity above 
that floor [%.e. of the genital sacs], from which they have no other 
escape than through the channels leading into the main cavity of 
the body, from which they pass along the medial canals of the 
arms into the pouches formed by the foldings of their margin’, 
where they undergo their first development.”’ In figure 9 of his 
plate viii. he represents some of the pouches containing “eggs and 
planule.” Speaking of Cyanea, he says:—‘‘The eggs of Cyanea 
are able to lodge between the plications of the inner surface of the 
actinostome, though not provided with special pouches as in Aurelia.” 
Thus Agassiz clearly recognized the fact that the embryos of Aurelia 
are carried in special pouches; but he wrongly describes their 
formation as foldings of the margin of the arm; and, moreover, he 
states that the embryos do not reach them till they have attained 
the planula condition. If this is the case in Aurelia flavidula, it 
certainly is not so in d. aurita. I have succeeded in finding in the 
pouches embryos in all the stages described and figured by Claus 
1 The italics are not Agassiz’s. 
