IMS BRITISH PALAEOZOIC ASTEROZOA. 



deep down in the bottom, only the extremities of some of the arms reaching up 

 over it. These extremities are in constant movement, feeling about over all the 

 small particles in the vicinity, and now and again coiling round and grasping some 

 few of them, the food being then drawn down beneath the surface of the bottom to 

 the mouth. ... I have examined several hundreds of specimens taken at 

 different places and seasons, without ever finding anything in their stomachs 

 beyond more or less finely sorted bottom detritus, with the micro-organisms and 

 skeletal parts therein contained. . . . Possibly they may, like Echinocardium 

 cordatum, accidentally encounter small young molluscs and pass the same into their 

 stomachs together with the detritus of the bottom. . . ." 



(3) More or less mobile arms ; not living buried in the bottom. 



a. Ophiueoidba. 



Arms only slightly mobile : Ophiothrix fragilis, Abgd., Ophiopholis aculeata, 



Mull. 



Arms very mobile: Ophioglypha (five species). 



" The two first-named species, which in aquaria often sit motionless for days in 

 their hiding-places, are, in conformity with this, mainly detritus-eaters; they can, 

 however, according to Eichelbaum, also devour animal food. This writer has 

 found in the contents of the stomach indubitable remains of worms (soft parts with 

 setae still attached), crustaceans, remains of small Echinoderms and young bivalves, 

 besides detritus. 



" The Ophioglypha species, on the other hand, which have very mobile arms, 

 and will in aquaria fling themselves with astonishing rapidity and accuracy upon 

 pieces of meat, small molluscs and similar animal food, are distinctly carnivorous 

 detritus-eaters. They are often found with remains of small molluscs or crusta- 

 ceans in the stomach ; on examining a quantity of specimens, however, a compara- 

 tively large number will always be found quite empty. Experience has shown 

 this to be a good sign that the animal in question is carnivorous ; the greater the 

 extent to which an animal is constrained to live on prey, the greater will be the 

 percentage found with perfectly empty stomachs, evidently on account of the 

 length of time which frequently elapses between one capture and the next. The 

 Ophioglypha species, besides animal fond, also eat detritus. 



"0. fexturata lives, for instance, in the Limfjord, where it is found at most 

 places in quantities (up to 71 specimens per Ol nr.) almost entirely on detritus, 

 as a rule with a number of large bottom diatoms. In the Kattegat, on the other 

 hand, the species feeds chiefly on small bivalves such as Abra alba, small Crusta- 

 ceans such as Gammaridas, Mysidse and Diastylis, the young of Echinocardium 

 and winged insects (probably bees) ! The last find indicates that they occasionally 

 condescend to feed on carrion. . . Finally Ophioglypha occasionally devours 

 smaller specimens of its own species." 



