MEDUSAE. 743 



food of the Cydippe. The vitality, or perhaps the irritability, of the cilia is very endur- 

 ing, for they continue to act when the animal is cut into several parts, or even when a little 

 piece is nipped off, and will carry the severed portions through the water quite merrily. 

 The development of the Cydippe is very interesting, the young being produced from 

 minute vesicles, and passing through a series of stages before they assume their per- 

 fect form. 



IF the reader will now refer to the illustration on page 740 he will see a long, flat, 

 ribbon-like creature edged with a delicate fringe of cilia. This curious being is called 

 VENUS' GIRDLE, and from its beauty fully deserves the name. 



This lovely creature is found in the Mediterranean, where it attains to the extraor- 

 dinary length of five feet, the breadth being only two inches. Rightly, the words breadth 

 and length ought to be transposed, as the development is wholly lateral. The mouth 

 of the Venus' Girdle may be seen in the centre of the body, occupying a very small 

 space in proportion to the large dimensions of the creature to which it belongs. A very 

 good idea of the appearance of the Venus' Girdle may be obtained By supposing a 

 Cydippe two inches in length to be flattened and rolled out into a ribbon of five feet in 

 length. 



Owing to the great length and tenuity of this creature, it is seldom found quite entire, 

 but it seems to care little for the loss of a foot or so of its substance. 



WE now come to a very large order of acalephs, including all those beings which 

 are so familiar under the title of JELLY FISHES, SLOBBERS, and similar euphonious 

 names. They are all united under the name of Discophora, or disk-bearers, because they 

 are furnished with a large umbrella-like disk, by means of which they are enabled to 

 proceed through the water. 



Each order is separated into several tribes, the first of which is termed Gymnophthal- 

 mata, or Naked-eyed Medusae, because the little ocelli, or eye-specks, are either 

 uncovered or altogether absent. The edge is either simple or branched. The name of 

 Medusae is given to these creatures on account of the long trailing filaments which de- 

 pend from them like the snaky locks of Medusa from her head. In the Naked-eyed Me- 

 dusae, the circulating vessels may be seen radiating to the edge either simple or branched. 



The little figure in the upper left-hand corner affords an example of the family Sar- 

 siadae, which contains several genera found in British seas. All the Sarsiae are pretty 

 little creatures, and may be known by the four simple nutritive vessels and the egg- 

 tubes placed in the footstalk. In this genus the umbrella is nearly hemispherical, and 

 there are four tentacles set at the ends of the radiating vessels. 



Though small, the Sarsiae are interesting to the naturalist, on account of the curious 

 method by which the young are produced, sprouting like buds from the footstalk, and 

 presenting a very strange aspect as they project in different stages of development. In 

 their first stage, the young Sarsiae are nothing more than simple prominences upon the 

 surface of the footstalk, and gradually increase in size, developing first one part and 

 than another, until at last the little creatures are quite perfect, shake themselves free 

 from the parent, and commence an independent existence. 



There is a curious species of this genus, Sarsia prolifera, in which the base of every 

 tentacle is supplied with a little bunch of young Medusas, some just making their first 

 appearance as mere lumps of gelatinous substance, some half-grown, and others nearly 

 ready to free themselves from the parent stock. 



The last figure in this illustration is an example of another family, known by the 

 branching vessels. It this genus the umbrella is rather more globular than in either of 

 the preceding cases, and the vessels are six in number, each being twice divided into 

 two smaller vessels. The footstalk is short. 



THE members of the next family are known by their flattened disks and the egg-tubes 

 running linearly along the vessels. The left-hand figure represents a rather curious genus 

 which is devoid of footstalks and appendages, and has a disk almost as flat as a biscuit. 

 The simple radiating vessels are well shown in the illustration. The right-hand figure 



