100 ECHINODEEMATA. 



many are disfigured by monstrosities in the irregular evolution, both in 

 size and number of the renovating parts. 



On the tenth of June, a single ray was found, which had either 

 separated from an entire specimen, or was the residue of one having lost 

 the other parts. It shewed no symptoms of reproduction at the time ; 

 but, on the fifteenth, the rudiments of four additional rays were indi- 

 cated by four papillar prominences, projecting the sixteenth of an inch 

 from the broader end. Next evening, one of these had attained nearly 

 double the size : the others were less advanced, but a small orifice, the 

 mouth, was forming in the centre. The whole ray now extended about 

 thirteen lines. 



Another specimen having fallen to pieces from the extreme heat of 

 the season, rendered me apprehensive that this would share the same 

 fate ; nevertheless it escaped. Reproduction advanced vigorously, and 

 in two or three days longer, it appeared as in Plate XVII. fig. 3, upper 

 surface ; fig. 4, under surface. Some smaller specimens were now perish- 

 ing by the heat. 



This regenerating animal having begun to feed on June 29 and 30, 

 it dwelt for hours over a portion of mussel. In a month from the com- 

 mencement, the new organs appeared as in fig. 5. But, on the 15th of 

 July, the original ray fell to pieces, leaving the disc, fig. 6, surrounded by 

 the four generating organs. This was a singular incident, especially as 

 the animal became symmetrical, and fed soon afterwards. Nothing dis- 

 proportionate, or offensive to the eye, remained by privation of the un- 

 wieldy ray, and in ten days, or on July 25, the specimen, such as it re- 

 mained, was quite vigorous. But, while still enlarging, it perished sub- 

 sequent to August 15, at which time no indications promised reproduc- 

 tion of the fifth or defective ray. 



Mutilation is not incident either to size or age. It takes place, and 

 is succeeded by reproduction, alike in old and in young specimens. It 

 may be called total or partial. Several specimens having been collected 

 towards the middle of July, one consisted of only two rays, each two 

 inches and a half in length, issuing from opposite sides of the disc. 

 Wishing to ascertain some facts in reproduction, I endeavoured to pre- 



