154 ECHINODERMATA. 



tially open, cunningly inserted one of its rays between the valves, 

 and, thus gradually insinuating itself, destroyed its victim.* Mo- 

 dern observations do not, as far as we are aware, fully bear out the 

 above opinion of our ancestors as to the mode in which star-fishes 

 attack oysters ; although the destruction which they cause is pretty 

 generally acknowledged. The observations recorded by M. Eudes 

 Deslongchamps upon this subject are however exceedingly curious.*)* 

 As the waves had receded from the shore, so as to leave only one 

 or two inches of water upon the sand, he saw numbers of Asterias 

 rubens rolling in bunches, five or six being fastened together into 

 a sort of ball by the interlacement of their rays. He examined a 

 great number of such balls, and constantly found in the centre a 

 Bivalve Mollusc (Mactra Stultorum, Lin.) of an inch and a 

 half in length. The valves were invariably opened to the extent 

 of two or three lines, and the star-fishes were always ranged with 

 their mouths in contact with the edges of the valves. 



On detaching them from the shell which they thus imprisoned, 

 he found that they had introduced between the valves large 

 rounded vesicles with very thin walls, and filled with a transparent 

 fluid. Each Asterias had five of these vesicles ranged around 

 its mouth, but they were of very unequal size ; generally there 

 were two larger than the rest, equal in size to large filberts, 

 while the other three were not bigger than small peas. These 

 vesicles appeared to be attached to the Asterias by short pedicles, 

 and at the opposite end of each was a round open aperture, through 

 which the fluid contained in the vesicle flowed out drop by drop. 

 No sooner was the animal detached from the shell that it was thus 

 sucking, than the vesicles collapsed and became no longer distin- 

 guishable. The Mactra were all found to be more or less de- 

 voured, some having only their adductor muscles left; but, however 

 little they had been injured, all had lost the power of closing their 



* This maybe gathered from Aldrorando, who writes as follows : " AHi ostrea- 

 rom bostes soot Stella; marina? moll& cntsti intectae, rer&am crodeltter, (at JElianos, 

 Kb. ix. cap. 22, ait,) iotmicae ot hcc ipsas exedant et confidant Ratio iosidiantm qoas 

 eis molhmter ejosmodi est. Com testacea soas patefaciant conchas, com vel refri- 

 geratioaeegeot,Telotaliqaidpeittnensadirictam iocidat; eae, ooo de sois stve cnmbos 

 sire radii* infra testas ostreae biaotis iosito eas clandi probibens, came implentar." 

 Testae, lib. iiL page 497. Tbos likewise Oppian, 



" Sic strait insidias, sic sobdola fraodes 

 Stella marina para L, sed mil to adjota lapillo 

 Whiter, et pedUms scabris disjuogit Mantes." 

 t Bulletin des Sciences de M. le Baron Ferossac, vol. *. p. 296. 



