Chap. I. HISTOLOGY OF CORYNE MIRABILIS. 



203 



as is generally the case, they contract into little knobs at several points along 

 their length, and bend at sharp angles iipon themselves. (Compare wood-cut 29, 

 page 212.) 



The peculiarities of the medusoids, which are developed at the latter end of 

 the breeding season, have already been pointed out in brief (page 189). We will 

 here revert to them, and describe the nature of these apparent anomalies in a 

 more detailed manner. The medusoid goes on developing, after the usual manner, 

 for the greater part of the period of its embryonic growth, and then there follows 

 an excess of development in some of the organs, and a deficiency in others. The 

 proboscis grows to an enormous size, so that in the females (PI. XVII. Fiq. 16, n\ 

 with the walls full of eggs, it occupies the whole cavity of the disk, and projects 

 for beyond it; and in the males (PI. XVIII. Fig. 11, «), being gorged with mature 

 spermatoza, it crowds upon the walls of the disk as much as in the females. At 

 this stage it is very active, and constantly changing its shape ; at one time the 

 end is sharp (PI. XVII. Ficjs. 12, 13, 14, and 16), at another blunt {Fig. 15), and 

 then broad and pear-shaped {Fig. 11). Sometimes it distends itself with chymiferous 

 fluid {Fig. 16) till it protrudes far beyond the edge of the disk, and then again 

 suddenly contracts to moderate dimensions. In no instance could a mouth be 

 discovered at the end of the proboscis. The radiating and circular tubes are 

 developed to perfection, and oftentimes the radiating tubes are more than four in 

 number, varying from five {Figs. 13 and 15) to seven, and not always arranged 

 symmetrically around the disk. The tentacles vary in the degree of development 

 to which they arrive, some medusoids, in fact, have not any {Fig. 13), or only some 

 very slight protuberances in their places {Fig. 14, r); others have quite prominent 

 papilte {Figs. 11, 15, and 16), growing longer and longer, till, in some instances, we 

 find them with tentacles as long as the disk is high {Fig. 12). In the latter cases 

 the tentacles have a stiflf, jagged, and awkward appearance, very unlike the graceful 

 and flexible forms of the perfectly formed embryo; nor have they any swelling 

 at the base, nor an eye-speck, but simply a slight thickening of the outer wall 

 (PI. XIX. Fig. 9, «), which suddenly thins out below. The eggs, occupying a space 

 between the inner and outer walls (PI. XVIII. Fig. 2P, h a\ are discharged by 

 rupturing the outer wall («). The transverse partition (PI. XVII. Fig. 12, pr\ in 

 some of the more fully developed medusoids at least, has all the perfection' of 

 the same organ in well-matured embryos, and may be seen flapping upward and 

 downward as the water rushes in and out with the expansion and contraction of 

 the disk. The withered and wrinkled condition of the majority of these abnor- 

 mally developed medusoids, justifies the inference that they do not become free, 

 but cast their eggs or spermatoza, and then shrivel up and die. Some of the' 

 more normally developed of these forms (PI. XVII. Fin. 12), perhaps, do at least 



