(14) 



EXPLANATION OF THE PLATES. 



eight tentaclos on nno lioail and only four on the 



other. 100 diameters. 

 Fig. 3ra. The same as fig. a 7, with the tentacles retracted. 

 Fig. 38. A forked tentacle. 100 diameters. 



PLATE Xa. 

 ScYPHOSTOM.\ OF Cy.\xk.\ aectic,\ and Aukelia 



FLAVIDl'L.^, ETC. 



[T'ifjs. 1, -2, 3, 4, 4a, 5, 6, 7, 8, 10, 11, li, V2o., 14, .ind 15 are ilraivii 

 by H. J. Clark; tijjs. 4b, 9, 13, 1.5a, 10 to 41, by A. SouitI.] 



All the fignres by II. J. Clark, and fig. 0, are Cyanea are- 

 tica ; and all those by A. Sonrel, excepting fig. !>, are 

 Aurelia flavidula. Unless when stated otherwise, the 

 following letters refer to the same jiarts: u outer 

 ■wall of the body ; o' outer wall of the tentacle ; »" 

 lasso-eells; <i' end of the tentacle; h inner wall of 

 the body ; i' inner wall of the tentacle ; h- radiating 

 partition in the body ; h" transvei-se wall of the cells 

 in the axis of the tentacle ; c mouth ; c" proboscis ; 

 c' base of the body ; (/ digestive cavity ; <j c' tenta- 

 cles ; f, horn-like sheatli ; p, Purkinjean vesicle ; Jc, 

 Wagnerian vesicle ; y, }olk. 



Fig. 1. The mouth and one tentacle of an eight-armed 

 scyphostoma. 500 diameters. 



Fig. 2. Partially retracted tentacle of a four-armed scy- 

 phostoma. 500 diameters. 



Fig. 3. Contracted tentacle of an eight-ai-med scj-phostoma. 

 500 diameters. 



Fig. 4. An eight-armed scyphostoma, showing the strongly- 

 contracted tentacles, the mouth wide open, and the 

 horn-like sheath. ■.'0() diameters. 



Fi". 4a. Base of fig. 4, to show the details of the horn- 

 like sheath. 500 diameters. 



Fig. 4''. Similar to fig. 4, but the tentacles only partly 

 retracted. '200 diameters. 



Fig. 5. Actinal end of an eight-armed scyphostoma to 

 show the details of the month, radiating pai'titions, etc. 

 200 diams. The arrangement of the cells around the 

 mouth and along the tentacles shows an nmnistak- 

 able resemblance to the plates forming the borders 

 of the corresponding parts in Echinoderms, and espec- 

 ially in Star-fishes. 



Fig. G. Basal portion of fig. 20, PI. X., to show the 

 cellular structure of the walls, n' outer surface of tlie 

 outer wall (ii) ; h^ outer surface of inner wall (/<). 

 500 diameters. 



Fig. 7. Tentacle of fig. 14, PI. X., to show the lasso- 

 eells. 500 diameters. 



Fig. 8. Cells from the inner surface of the inner wall 



of fig. US PI. X. 500 diameters. 

 Fig. 0. A to G lasso-cells of a fuU-growu Cyaiiea. a 



the wall of the cell; b the coil. 500 diameters. 

 Fig. 10. Lasso-eells from the tentacle of Fig. 14, PL X. 



500 diameters. 

 I"ig. 11. The second set of tentacles half developed, and 



two of the first set forked. 100 diameters. 

 Fig. 12. Shows one hydi'a fi.xed temporarily in the 



mouth of another. ItMj diameters. 

 Fig. ]2-\ Actinal end of A, fig. 12. 

 Fig. 13. The third set of tentacles partially developed. 



1'^ intervals between the radiating partitions (Jr). 100 



diameters. 

 Fig. 14. Actinal end of a scyphostoma with ten tentacles, 



ilcveloped in fives, and the mouth five-sided. 100 diams. 

 Fig. 15. Actinal end of a scyphostoma witli fourteen 



tentacles, in various stages of growth ; the numbers 



refer to their relative ages. 100 diameters. 

 FiiT. 15-'. Similar to fig. 15, but very much contracted. 

 Figs. 1() to 24. The serial development of the egg; taken 



from the o\ary of a full-grown Aureha. 200 diams. 

 Figs. 25 to 3G. The progressive development of the free 



sc\'phostoma planula of Aureha. Figs. 20, 27, 28, 



30, 31, and 32 from the ovary; figs. 25, 29, 33, 34, 



35, and 3G from the pouches. 200 diameters. 

 Fig. 37. The proboscis and se.\ual organs (c) of fig. 22, 



PI. XJi. (( lips ; a' incipient fringes of the edge of 



the proboscis ; d aperture of the month. 20 diams. 

 Figs. 39, 40, and 41. Details of the proboscis of fig. 37, 



with the same letters. 



PLATE XL 



StKODIL.V of ArKELI.\ FL.iVIDCL.^. 

 [Drawn by A. SourcL] 



Unless otherwise stated, all the figures are magnified 15 

 diameters. In all the figures of Plates XL, XI^., Xlb., 

 and XI''., the following letters refer to the same parts, 

 unless otherwise stated. 



For the scyphostoma, c is the mouth or proboscis ; c' 

 base of body ; c° c' c* oft'shoots from the body ; d 

 digestive eavity ; e e' tentacles \ 'J <f <f ff '/ ff' constric- 

 tions preparatory to the formation of the saucer-shaped 

 disks. 



For the ephyra, a is the proboscis ; a' the month or lip ; 

 <r the cavity of a ; h the digestive cavity ; V limit of h ; c 

 chymiferous canal leading to the eyes; c' c- branch of 



