SEA-URCHINS AND SEA-CUCUMBERS 339 



closely allied to the Chirodota. It is very common in the 

 Adriatic and Mediterranean seas, but has not yet been 

 taken on the British coasts. I would counsel you, how- 

 ever, to have your eyes open if you have the opportunity 

 of searching our coasts; for, as Miilier found one species, 

 the Synapta inhcerens, on the shores of Denmark, it is not 

 at all unlikely that we may possess either it or some other. 

 Should it ever come into your hands, slit open the skin of 

 the belly, where you will find, imbedded in little papillae 

 or warts, some highly curious spicula or calcareous forms. 

 Each consists of an oblong plate, perforated with large 

 holes in a regular manner, and having a projection on its 

 surface near one extremity, to which is jointed 

 a second piece, having the most singularly true 

 resemblance to an anchor. The flukes of this 

 anchor project from the skin, the shank stand- 

 ing obliquely upward from the plate, to which 

 it is articulated by a dilatation, where the ANCHOR-PLATE IN 



SYNAPTA. 



ring would be, which is cut into teeth. 



Among the multitude of transparent creatures that swim 

 in the open sea, few are more interesting than those which 

 constitute the infant state of the very animals that we have 

 lately been examining the Sea-urchins and their allies. 

 It is a productive way of obtaining subjects for micro- 

 scopic research, to go out in a boat on a quiet summer's 

 day, especially in the afternoon, when the sun has been 

 shining, or when evening is waning into night, and with 

 a fine muslin net stretched over a brass ring at the end 

 of a pole skim the surface of the smooth sea. At inter- 

 vals you take in your net, and having a wide- mouthed 

 glass jar ready, nearly filled with sea-water, invert the 

 muslin in it, when your captives, small and great, float 



