﻿Dec, 1 85 6VJ 



ELLIOTT SOCIETY.. 



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with scalloped rim. This strongly reminds us of the pGlyxenia 

 cyanostyla of Eschscholtz, save only that from the small number 

 of details given of that species we hardly have as much ground 

 for considering it a true Medusa, as we have shown for this stage 

 of our Turritopsis larva. Unfortunately, I know only Blainville's 

 copy of his drawing, having been, up to this time, unsuccessful in 

 procuring the " System der Acalephen" of the German naturalist. 

 In this figure, if it is a faithful copy, there is no indication of sense- 

 bodies of any kind, either of sight or hearing, there are no radi- 

 ating and no circular tubes, and these are represented by simple 

 triangular projections of the digestive cavity that proceed centri- 

 fugally to the bases of the tentacula, which are alternately long and 

 short. We have also in this figure no indication of a vail, and the 

 only feature which remains to be noticed is the marginal row of areas 

 between the tentacula and the digestive cavity, which are doubtless 

 homologous with the muscular lobes of the Turritopsis larva. The 

 only two differences that need be noticed, are the greater number 

 of tentacula, and correspondingly more numerous " triangular areas ,r 

 or projections from the stomach, and the absence of lobation round 

 the disk in P. cyanostyla. With regard to the former, it is no more 

 than the difference between Stomobrachium and Thaumantias, and 

 the latter is only such a difference as exists between young and adult 

 Medusae iu the genus Sarsia. Indeed, among the vail-bearing Me- 

 dusae lobation of the disk-border seems to be rather an embryonic 

 peculiarity, so that, as a general rule, we might almost at once 

 decide that of two adult Naked-eyed Discophores, that which has a 

 lobed margin, is of a typically lower grade than that which has not. 



But the description of Stenogaster complanatus (Kolliker) also 

 shows a Medusa, found at Messina, having, in all essential respects, 

 a close resemblance with the last stage of the Turritopsis larva. 

 The number of tentacula and otolithic capsules is double that of 

 these parts in our embryo, and there is only one otolith in each 

 capsule. Both, however, are colourless small medusae, with scal- 

 loped ("wellenformig Rand," Koii.) margin to the disk, — each 

 possesses a vail running up between the lobes of the disk, simple 

 mouth, and stiffish, striate tentacula, each with a radix. Neither pos- 

 sesses chymiferous tubes, and the simple mouth in both sometimes 

 assumes the four-rayed form. The little conical knob of the Steno- 

 gaster complanatus, is evidently analagous to the similar process 

 which surmounts the centre of the disk's upper surface in several 

 Medusae, and has only the value of a specific distinction. 



