THE VENT. 



21 



the surface of the shell, and thus, in conjunction with the prickles, protect it from injury." 

 Professor Edward Forbes, in discussing the function of the Pedicellarice, says, " If they 

 be not distinct animals, as Mliller fancied, for what purpose can they serve in the economy 

 of the star-fish ? If they be parasites, to what class and order do they belong ? — what 

 is their nature, and what is their food ? Truly, these are puzzling questions. These 

 organs or creatures have now been known for many years, have been examined and ad- 

 mired by many naturalists and anatomists, have been carefully studied and accurately 

 dehneated, and yet we know not what they are. This is but one of the mysteries of 

 natural history — one of those unaccountable things which we know and know not — of 

 those many facts in nature which teach us how little is man's knowledge, and how won- 

 drous and unsearchable is God's wisdom. It is folly and vanity to attempt to account 

 for all facts in nature, or to pretend to say why the great Creator made this thing, and 

 why He made that, and to discover in every creature a reason for its peculiar organization. 

 It is but another form of the same vanity, having satisfied itself of the discoveries it has 

 made, to pretend to praise the all-wise Maker's wisdom in so organizing His creatures. 

 That God is all-wise is a revealed truth ; and whether the organization before us seem 

 excellent or imperfect, it matters not — we Jcnow it is perfect and good, being the work of 

 an all-wise God."^ 



The Vent. 



It was long believed that the Asteriadce were destitute of an anal opening, but a more 

 careful study of the organization of these animals has proved this was an error. Baster,^ 

 in reference to Uraster rubens, wrote : — " Utrumque genus (Echinorum et Stellarum 

 marinarum) os inferne, et ad excrementa ejicienda aperturam superne habent." 



Janus Plancus^ observed : — " Prseterea hae stellse anuni in medio oppositum ori, uti 

 Echini, veluti umbihcum quemdam gerunt et in acumen attollunt." Miiller* describes, in 

 the Asterias ■militaris, a central spot as " macula verruciformis," and says as this spot is 

 not perforated, therefore Baster's description of the anus could not be correct. 



Tiedemann, in his great work, denied Baster's statement, and treated his observation 

 as a mistake ; since the publication of that treatise, the same opinion has been expressed 

 in nearly all modern zoological works. This discrepancy about an anatomical fact has 

 arisen from the error of deducing general conclusions from limited observations ; for it 

 now appears that, of the eighteen genera of star-fishes described by Miiller and Troschel 



1 Forbes, ' British Star-fishes,' p. 98, 99. 



2 Baster 'Opuscula subseciva,' p. 116. 



^ ' Epistola de incessu marinorum Echinorum. Opuscula Instituti Bononiensis,' torn, v, pars i, p. 245. 

 * ' Zoologia Danica,' cxxxi, p. 14. 



