280 GENERAL REMARKS. 



often, as in Taenia, accompanied by corresponding 

 acceleration and loss of primitive stages. The curious 

 transformations of Echinodermata are plainly adapta- 

 tions of the larvae to a free life in the water before 

 they become attached or sink to the bottom and begin 

 their proper hfe as crawlers. In this class there are a 

 number of examples of acceleration (Comatula, Spa- 

 tangoids, etc.). Such life-histories and those of Epi- 

 cauta, Sitaris and Meloe among Beetles which run out 

 the gamut of changes from the simplest Thysanuri- 

 form larva through several grub stages to the quiescent 

 pupa, show that the most complicated metamorphoses, 

 called hypermetamorphoses by entomologists, must 

 have arisen in response to the changes of the surround- 

 ings. No other hypothesis can account for the num- 

 ber, variety, and novelty of these metamorphoses and 

 their suitabiUty to the number, variety, and novelty of 

 the changes in the surroundings and the corresponding 

 changes in habits of the larvae at different stages of 

 growth. 



The occupation of the larval stages by strange and 

 curious forms, like caterpillars, grubs, etc., naturally 

 attracts attention and at first makes one wonder at the 

 apparent eccentricities of nature's ways. But in reality 

 they serve to throw a strong side light upon the normal 

 mode of action of the laws of heredity, and show us 

 that, in spite of its enormous conservative force, hered- 

 ity is subservient to the effects of habit or use of parts. 



That these secondary larval forms are more re- 

 duced, although more specialized organisms than the 

 primitive Thysanuriform larvae, has already been stated. 

 Among Coleoptera and Neuroptera this is obvious 



