in.] METAMORPHOSES OF INSECTS. 59 



ally loses its power of swimming, and, sinking to the 

 bottom, looses the bands of cilise, and attaches itself 

 by its base to some stone or other solid substance, 

 the knob of the club being free. The calcareous 

 framework increases in size, and the expanded head 

 forms itself into a cup, round which from five to 

 fifteen delicate tentacles,, as shown in Fig. 44, make 

 their appearance. 



In this stage the young animal resembles one of 

 the stalked Crinoids, a family of Echinoderms very 

 abundant in earlier geological periods, but which 

 has almost disappeared, being, as we see, now re- 

 presented by the young states of existing more ad- 

 vanced, free, species. This attached, plant-like con- 

 dition of Comatula was indeed at first supposed 

 to be a mature form, and was named Pentacrinus ; 

 but we now know that it is only a stage in the deve- 

 lopment of Comatula. The so-called Pentacrinus 

 increases considerably in size, and after various gra- 

 dual changes, which time does not now permit me 

 to describe, quits the stalk, and become's a free 

 Comatula. 



The metamorphoses of the Starfishes are also very 

 remarkable. Sars discovered, in the year 1835, a 

 curious little creature about an inch in length, which 

 he named Bipinnaria asterigera (Figs. 45-47), an d 

 which he then supposed to be allied to the ciliograde 

 Medusae. Subsequent observations, however, made 

 in 1844, suggested to him that it was the larva of a 

 Starfish, and in 1847 MM. Koren and Danielssen 

 satisfied themselves that this was the case. 



Figs. 45 and 46 represent the front and side view 



