NANOMIA CAKA. 



200 



further development ; the terminal irydra of Fior. 346 increases greatly 

 in size ; a number of buds make their appearance on both sides of the 

 axis, immediately at the base of the float ; these buds are nothing but 

 the rudimentary swimming-bells, the so-called polyps and the tentacles. 

 (Fig. 347.) As the young Nanomia grows larger, these buds increase 

 in size, and we can soon trace in some of them undoubted polyps, 

 with an open mouth, and the rudimentary tentacular knobs accompa- 

 nying them ; immediately at the base of these polyps there is a small 

 transparent protuberance, the first appearance of the protecting scale. 

 The terminal polyp of this diminutive community increases greatly in 

 size, becomes open at the extremity, and covered irregularly with large 



Fi.c 34S. 



Fip. 350. 



patches of scarlet pigment-cells ; the tentacles become longer, and when 

 they equal in length that of the community, from six to eight knobs 

 hang from the main threads. (Fig. 348.) In somewhat more advanced 

 specimens, we find protecting scales already quite well developed 

 (Fig. 349), and besides many additional polyps in different stages of 

 development, such as are figured in Fig. 342 ; the buds immediately 

 under the float, the nature of w^hich seemed still doubtful in the last 

 stage (Fig. 348), are now seen to be rudimentary swimming-bells, some 

 of them nearly as advanced as those represented in Fig. 337 ; these 

 rudimentary parts grow now with great rapidity, the clusters of the 



Fio;. 348. The terminal Hydra is open, tentacles are developed, as well as clusters of small 

 swimming-bells, like those of Fig. 337, and of Medusae (feeding polyps), like those of Fig. 342. 



Fig. 349. Still more advanced Nanomia. 



Fig. 350. Young Nanomia, where we find several Medusa? (feeding polyps) of the first kind, 

 having all the characters of those found in the adult (Fig. 332), and embryonic swimming-bells. 



NO. u. 27 



