(10) 



EXTLAXATIOX OF THE PLATES. 



Fi^-, 



Fis. 



ncs? of tho ]>illai'> ami nt" tlicir ])ri)liiiii;atiim. 1111 

 the lour pillai-s : ,v ,< .< x tlio fun-ows almitr tlio middle 

 of the lowoi- t^mt'aee of the oral lobes ; (/ </ </ the oral 

 lobes, meeliiijr from below iu the centre of the figure 

 to shut the mouth ; o.f, os, os, the cut edges of the 

 sexual jiouehes. 



;plaius more fully the relations of the parts 

 represented in fig. IG. 3 oral ring: 4 thiekening of 

 the oral lobe tl bending over the mouth ; o.< ti)ld of 

 the sexual poudi. 



. IS shows how the sexual organs of are supported 

 in the folds of the sexual pouch (W. 

 . 1!1 shows the eonncetion of an oral poueli with the 

 concentric Iblds t' of the lower lloor. and. with the 

 tentacles / ^ connected with the sexual organs of. 

 . -'O. Lobes of a sexual pouch stretched out. <i ova- 

 ries; (;/' t<)lds formed by the ovaries; t their tentacles. 

 . il. LoIh's of the sexual jioueh of a young female. 

 tindevcloped o^ ary ; of folds of the ovary ; / their 

 tentacles. 



. 22. Lobes of a sexual pouch of a male stretched 

 out. o.< folds of the pouch passing into the concentric 

 folds of the lower IliKir: s spermatic cells; sf folds 

 of the speruuitic sacs : t their tentacles. 



Part of the lower floor, embracing one entire 

 ambulacrum o and one eutu'e iuterambnlaerum a, with 

 one half of the adjoining ambulacrum and interambn- 

 laeriim, to show the inequality of the width of the 

 ambulacral, c, and of the iuteranibulacral, c', chambers, 

 />■ /,■ being the gelatinous bands along which the u]>jier 

 and lower floors are united ; /" the tentacles, and (/' the 

 jioint where the folded ]>art of the lower tloor passes 

 into the folds of the sexual jiouches and into the pillars 

 of the digestive cavity. 



:. 24. Kamilications of the chymiferotis channels along 

 the margin of the disk. c tube of the eye ; n lobe 

 of the eye ; a interambulaeral incision ; o' a" intcr- 

 ambulacral lobes ; o' and o' ambulacral lobes. The 

 parts in black corres))Oud to the parts iu wliite of 

 fig. io, the cluuinels being kept light in fig. 2^ and dark 

 in fig. ■-':>. having been drawn upon difierent grounds. 



PLATKS VI.. VII., VIIL, and IX. 

 Aur.Ei.i.v Ki..vviDrL.\, Pu: and Zt.s'. 



[.\.ll the fijriires ol" these plates were drawn from nature by A. Sourel.] 



Pl.\te XI. represents our Aurclia from below, with sundry 



details. 



Fig. I. When the di>k is fully expanded, and the ap- 

 pendages of the lower side are in their natural position, 

 scvi'ral features appear iu this species, which seem not 

 to have been noticed in other allied Acalephs, The 

 mouth is closed by folds of the oral lobes, and one 

 of these tulds forms a transvei-se ridge across the oral 

 aj>erture. The oral lobes, or sivcalled arms, are not 

 stretched out at the same angles Avith one another, 

 but stand nearer each other on opposite sides in one 

 direction than in the other. In tlie ramifications of 

 the chymit'erous system it .should also be noticed, that, 

 of the sixteen simjile radiating tubes, eight reach the 

 base of an ocular apparatus, ;ind eight others, alter- 

 nating with them, anastomose with the marginal circular 

 tube without branching. 



Fig. 2. Segment of the same, the margin bc-ing arched 

 downward. This figure shows that iluring the con- 

 tractions of the disk r r. the oral lobes arc not pro- 

 jected beyond its margin, but arc bent along the fiu-row 

 fiirmeil by the curve, and the tentacles, h. thrown out. 

 eyes ; il <l chymiferous tubes : ti a tiilds of the 

 oral lobes (U- arms : e their stem ; / opening leatling 

 into a blind sac below the sexual poiu-h (this opening 

 is generally but falsely represented as leading into 

 the sexual cavity and communicating with the main 

 cavity). 



Fin. .'!. Oral opening laid open by the revi'i-sion of the 

 oral lobes ii' (r o', a remaining in place, o p^Tamid 

 of the centre of the disk projecting into the oral 

 aperture, which exhibits eight cmargiuations, fom-, i i, 

 in the angles corresponding to the base of the stems 

 of the oral lobes, and four, e e, in the direction of 

 the sexual jiouches, 



T\s. 4. Eve. as seen lacing the margin of the disk 

 where this is curved down. o eye : c c ocular lobes 

 of the margin of the disk ; c c, i i chymiferous tubes 

 of the ocidar apparatus. 



Fig, .'). Transvei-sc section of the oral arm of a male 

 individual, showing how much thinner its stem is than 

 that of the female, fig. 6. a stem of the oral lobes ; 

 h and c its two halves spreading to form the folds 

 or lobes, e <>, of the arms. 



Fig. G, Transverse section of the oral arm of a female 

 individual, a stem; h c its halves; ( e the folds 

 or lobes in the pouches of which the eggs are received 

 and remain until the young is freed to swim about. 



Pl.\ti: ^^L General view of Aurelia flavidula from above, 

 with structural details. 



Fig, 1, View of our Aurelia from above, iu which the 

 ovaries appear plainly through the transparent disk. 



