212 MISCELLANEOUS OBJECTIONS TO THE 



form), " this at least perfectly innocent and harmless struc- 

 ture ?" It may be suggested in answer, that the voice, which 

 is certainly of high importance to many animals, could hardly 

 have been used with full force as long as the larynx entered 

 the nasal passage ; and Professor Flower has suggested to 

 me that this structure would have greatly interfered with an 

 animal swallowing solid food. 



We will now turn for a short space to the lower divisions 

 of the animal kingdom. The Echinodermata (star-fishes, 

 sea-urchins, etc.) are furnished with remarkable organs called 

 pedicellariae, which consist, when well developed, of a tri- 

 dactyle forceps — that is, of one formed of three serrated 

 arms, neatly fitting together and placed on the summit of a 

 flexible stem, moved by muscles. These forceps can se*ize 

 firmly hold of any object; and Alexander Agassiz has seen 

 an Echinus or sea-urchin rapidly passing particles of excre- 

 ment from forceps to forceps down certain lines of its body, 

 in order that its shell should not be foaled. But there is no 

 doubt that besides removing dirt of all kinds, they subserve 

 other functions ; and one of these apparently is defence. 



With respect to these organs, Mr. Mivart, as on so many 

 previous occasions, asks : " What would be the utility of the 

 first rudimentary beginnings of such structures, and how could 

 such incipient buddings have ever preserved the life of a 

 single Echinus ? " He adds, " Not even the sudden develop- 

 ment of the snapping action could have been beneficial with- 

 out the freely movable stalk, nor could the latter have been 

 efficient without the snapping jaws, yet no minute, merely 

 indefinite variations could simultaneously evolve these com- 

 plex coordinations of structure ; to deny this seems to do no 

 less than to affirm a startling paradox." Paradoxical as this 

 may appear to Mr. Mivart, tridactyle lorcepses, immovably 

 fixed at the base, but capable of a snapping action, certainly 

 exist on some star-fishes ; and this is intelligible if they serve, 

 at least in part, as a means of defence. Mr. Agassiz, to whose 

 great kindness I am indebted for much information on tne 

 subject, informs me that there are other star-fishes, in which 

 one of the three arms of the forceps is reduced to a support 

 for the other two ; and again, other genera in which the third 

 arm is completely lost. In Echinoneus, the shell is described 

 by M. Perrier as bearing two kinds of pedicellariae, one re- 

 sembling those of Echinus, and the other those of Spatangus; 

 and such cases are always interesting as affording the means 

 of apparently sudden transitions, through the abortion of one 

 Of the two states of an oi»«9* - 



