92 



therefore venture to conjecture that they do not cast their 

 spines nor case, as lobsters do. 



These things are extremely difficult to make out; and if 

 we should make any mistake, it may be so far successful as 

 to be the cause of finding out the truth. 



There is the same species recent at the British Museum j 

 and one of them has tht; spines over the foraminous aper- 

 tures turned back : perhaps, they are commonly so when 

 alive. We do not know from whence they come. 



On looking over Klein, we found a figure which appeared 

 to be the same as ours, and which Gmelin quotes as 

 var. a. of his Echinus cidaris. We also find a specimen in 

 Mr. W^oodd's most respectable collection, which seems to 

 have been taken in a living stale. On examining all the 

 specimens with a great deal of attention, we find the fo- 

 ramina constantly different from the New Holland one; we 

 therefore suspect that it is another species, and ought to 

 have a new name. The double foramina are situated in. 

 simpler-formed bones, which are thickest at one of the 

 ridges; when the animal's mouth is downwards, jhey seem 

 to lap over each other like tiles. The New Holland one has 

 strong indentations between the double foramina, and the 

 bone forms a kind of beak-like process, curving into the 

 holes — see figs. 1. 2. As these animals are often admired 

 when destitute of spines, it may be necessary to observe 

 another difference in the bones. The five divisions destitute 

 of foramina have, as we before observed, six rows of 

 spines ; consequently they have six rows of tubercles, 

 suited for the sockets of the spines, somewhat distant. 

 Those from New Holland are more equal in size, more 

 crowded and numerous : see figs. 3.4. 



We do not think that the figure of a petrified specimen 

 referred to by Gmelin, in Klein, is the same species. We 

 have specimens sufficiently preserved to see the difference, 

 which Will be figured in tab. 132 of British Mineralogy, 



