258 KAMBLES OP A NATUKALIST. 



which almost looked as if they had been hollowed 

 out by the hand of man. Besides this, the waves, 

 which had penetrated between the interstices of the 

 two ranges of rock, too hard to be entirely broken 

 through, opened a channel inland and gradually 

 formed small grottos, which were sometimes par- 

 tially vaulted over, and at other times wholly exposed 

 and uncovered. Many of these cavities gave a 

 miniature representation of the well-known pheno- 

 menon observed in the grotto of Capri. When our 

 boat, lying at the entrance of one of these caves, 

 intercepted the direct rays of light, they passed 

 below our keel, and, being refracted in the crystal 

 liquid, gave rise to the same effect as that produced 

 by a prism, and bathed the rocks and the foam- 

 crested waves in the richest azure tints. 



We found at Favignana almost all the animals of 

 which we had lost sight ever since we left Torre 

 dell' Isola. The Medusae and their kindred allies 

 were, however, of much rarer occurrence, probably 

 in consequence of having been carried away by 

 some opposing currents. We met with only a few 

 Alcinoes *, some large Beroidas, and an infinite 

 number of Pelasgiae. The recesses and the basins 

 to which I have already referred were, however, 

 unusually rich in all littoral species. The annelids 

 especially presented numerous varieties. It was at 

 Favignana that M. Milne Edwards found his My- 

 riana, which bears a chaplet of six individuals 

 united end to end in such a manner that the last 

 of all has no other nourishment but the food which 



* The genus Alcinoe belongs to the family of the Beroidse, of 

 which I have already spoken. 



