MUSEUM OF COMPARATIVE ZOOLOGY. 145 



by me very completely developed, as long as the union of their parent to 

 the first Lizzia remained unbroken. In addition to a well-developed bud, 

 which, as Sars pointed out, seems in its growth far in advance of the remainder, 

 we find other buds, now to be described, in various stages of development, from 

 a simple hernia-like protuberance of the walls of the proboscis to a sphere 

 united at one pole to the parent. Each seems in its early stages to be enclosed 

 in a separate capsule, which is ruptured at the time when the bell opening is 

 formed, long before the final separation of the bud from its parent. The re- 

 mains of the capsule after the rupture are then absorbed by the parent. In 

 the youngest buds from the proboscis of a Lizzia, four of the tentacular bulbs 

 are very large and consjiicuous. These bulbs are situated at the junction of 

 radial tubes, with a circular vessel. From each of them arises a single club- 

 shaped and hollow tentacle, which, with the three other primary tentacles, is 

 nicely folded over the future opening of the bell cavity above the future veil. 

 In this stage, before the capsule in which the young medusa is contained is 

 ruptured, the four tentacular bulbs, which become the ocelli, are large, and 

 form the most conspicuous structure in the bud. In the same stage the pro- 

 boscis is a club-shaped bodj^, almost filling the whole upper part of the bell 

 cavity, and has the free end bifid, thus prophesying the future oral tentacles. 

 Each of the bifurcations is thickly set with lasso-cells, but is destitute of knob- 

 like bodies mounted on pedicles. The mouth is as yet closed. The next 

 oldest stage to that last described in the growth of the bud is one in which 

 there are four radial tentacles, and the beginnings of four others intermediate 

 between them on the bell margin. This stage resembles in many particulars 

 a jelly-fish called Dysmorjjhosa fidguram, A. Ag. We have here eight tentacles, 

 of unequal size to be sure, and buds beginning to form on the proboscis, both 

 true characteristics of Dysmorphosa. A little later the surrounding capsule 

 breaks, and the bell opening, with its veil, is speedily formed, so that there 

 protrudes a well-developed medusa, only a little less mature than that shown 

 in Plate I. fig. 1. 



The order of appearance of new tentacles in the intermediate clusters is 

 different from that given by Mr. Agassiz,* and copied from him by Haeckel.f 

 The method of growth, more especially the addition of the new tentacles, is 

 as follows. 



The tentacles in the intermediate clusters appear singly, each one of its 

 cluster being well developed before the beginning of the next following. Good 

 figures of Lizzia, while in a stage with two tentacles in each intermediate 

 cluster, and at the same time with three in the radial clusters, are given by 

 Forbes. In fact a medusa with tentacles in this condition is the oldest which 

 he has figured. It is probably, as has been pointed out, a younger stage, for in 

 subsequent growth a third tentacle is added to each interradial cluster, and 

 thus we have a medusa in which the number of tentacles is three in all clusters, 



* North American Acalephae, p. 161. 

 t Das System der Medusen, p. 95. 

 VOL. VIII. — NO. 8. 10 



