62 



lization than in the latter order, where the unvarying repetition of 

 similar divisions all around the disc unmistakably indicates inferiority. 

 Moreover, in addition to this, we have a peculiar specialization of the 

 gelatiniform layer, which is embraced by the outer and inner walls of 

 this floor, or rather between the muscular layer and the inner wall ; 

 instead of repeating the peculiarities of the gelatiniform layer of the 

 aboral floor, as occurs in Aurelia, it has a totally different appearance 

 and consistency, and an almost unlimited degree of expansion and 

 contraction. In the tentacles it occupies a very deep space between 

 the outer wall, or rather the muscular layer, and the inner wall. 

 In this latter respect, Lucernaria is again peculiar, since in addition 

 to the muscular layer, which alone is present in the young, it devel- 

 ops this gelatiniform layer, — the musculo-gelatiniform layer, as I pro- 

 pose to call it, — the like of which does not exist in the tentacles either 

 of Steganophthalmata or Gymnophthalmata. In the auricles, we have 

 also a specialization peculiar to Liicernaria ; for in addition to the pig- 

 ment eye-spot which is imbedded in the base of the oral face of these 

 bodies, the auricles, which in the young cannot be distinguished from 

 the tentacles, gradua,lly thicken the outer wall as age advances, and 

 peculiar, granuliferous, adhesive vesicles are developed between the 

 cells. In the adult, their tentacular nature is almost, or altogether, 

 obliterated, and the swollen outer wall, together with the enormous 

 thickness of the musculo-gelatiniform layer, form an oval mass, thickly 

 studded with adhesive organs, by which they cling, in a most tena- 

 cious manner, to any body which they may touch. These organs, 

 and the base of the peduncle, are the only means of adherence 

 which Lucernaria possesses ; although it is true that the tentacles 

 are used, as in Aurelia, for prehension, they are, comparatively, very 

 weak, and can only serve to retain the prey, and never effect the 

 purpose for which the auricles are constructed. In consideration of 

 the very obvious ofiice of an auricle, I would propose the name anchor 

 for it. 



Were the above-mentioned features in the organism of Lucernaria 

 alone to be taken into account, there could be no hesitation in saying 

 that this genus should be considered as the highest of the class of 

 Acalephaj ; because of its highly complicated and specialized gelatin- 

 iform mass ; the high grade, and the peculiar and distinctive grouping 

 of its muscular system ; the definite and bilateral form of the genital 

 organs, as well as their saccular subdivision ; the two-fold nature and 

 disposition of the prehensile organs, the tentacles and anchors ; and, 

 moreover, that it belongs to an order separate from either orders of 

 Acalephas, because of the typical elements of its genital saccules, 

 which are altogether different from either the Steganoi3hthalmic or 

 Gymnophthalmic type of genitals ; and also on account of the an- 



