Common Crossfish. 143 



scarcely any limit short of the retention of the stomachy and of at 

 least one coecal appendage uninjured. As the Echinodermata, on 

 the one hand, all go through more or less complex metamorphoses, 

 and, on the other, never when adult multiply by gemmation, it is 

 obvious that the power of repairing injuries cannot be, as it has 

 been held to be, correlated either with the absence of metamor- 

 phosis, or with the power of reproduction by metagenesis strictly 

 so called. 



For the account of the structure of the Echinodermata generally, 

 see Johannes Miiller, Abhandlungen Kon. Akad. Wiss., Berlin, 

 for 1853, translated in part by Professor Huxley in the Annals 

 and Magazine of Natural History for 1 854, Ser. ii., vol. xiii. ; 

 Professor Sharpey, Article ' Echinodermata/ in Toddy's Cyclo- 

 paedia of Anatomy and Physiology. 



For a monograph of the Asteroidea, see Miiller und Troschel, 

 System der Asteriden, 1842. 



For an excellent account of the nerve system of the sensory organs, 



and of the power of repi'oduction of lost parts in the common 



Cross-fish {Asterias nihens), as also of that of the Solaster 



2)apposa, and Cribella oculata^ see Wilson, Linn. Soc. Trans., 



J 860, vol. xxiii., pt. i., p. 107. 



For an analysis of the tegumentary skeleton, see Gaudry, Ann. 

 Sci. Nat. Ser. iii., torn, xvi., 1851. 



For reviews of Miillcr's researches into the anatomy and develop- 

 ment of the Echinodermata, see Huxley, Ann. and Mag. Nat. 

 Hist., Ser. ii., vol. viii., 1851 ; Baur, Nova Acta, 1864, 

 PP- I7> SI- 



45. Common Crossfish {Asterias Rubens), 

 Linn. 



Dissected so as to show its digestive and motor systems. 



One of the rays, the central one of the trivium, has been cut 

 short, and more or less of the anti-ambulacral integument removed 

 from each of the other four, and from the central disk. In the 

 inter-radial space which is opposite to the ray which is cut short. 



