LOCOMOTIVE SUCKERS OF HOLOTHURIA. 239 



the last chapter, and which are protruded through 

 innumerable orifices that perforate the integument. 

 In some cases, as in Holothuriafrondosa, these suckers 

 are arranged in five series, disposed like the ambu- 

 lacra of the Sea-egg ; in other genera they are only 

 found upon the middle of the ventral surface of the 

 body, that forms a flattened disc wherewith the animal 

 creeps, somewhat in the manner of a snail. 



In Holothuria pentactes five longitudinal rows of 

 suckers traverse the skin, extending the length of the 

 whole body, commencing near the root of the ten- 

 tacula, and terminating at the posterior orifice ; and 

 it is by the adhesion of these suckers that the animal 

 is enabled to attach itself firmly to any solid sub- 

 stance. About a hundred suckers may, in a moderate- 

 sized specimen, be counted in each stripe. In some, 

 five or six or seven suckers are placed in a row, near 

 the middle of the creature's body, the number gra- 

 dually decreasing towards the extremities, while in 

 young specimens only a double row of these suckers 

 is met with. Thus the number of suckers appears to 

 augment with the age of the animal. These suckers 

 can be wholly retracted and sunk in the flesh, so that 

 the animal then seems entirely divested of external 

 organs. 



We learn from a paper by Mr. C. W. Peach, read 

 before the Royal Polytechnic Institution of Cornwall, 

 that a species of Holothuria, called the " Nigger," or 

 " Cotton-spinner/' by the Cornish fishermen, is very 

 common in deep water off" that coast, and is held by 

 them in great detestation, from its throwing out 

 what they call " cotton/' and also because where the 



