116 ECHINODEEMATA. 



Mutilation is inevitably concomitant on impurity of the water. But 

 without any obvious cause, we witness it continually, and to the most 

 destructive extent. Piece by piece falls off the rays, until nothing but 

 the disc remains, yet the animal still lives. After a specimen had been 

 preserved some time, only a very short fragment of the rays continued 

 entire ; } 7 et the subject fed greedily, nor was motion utterly extinct even 

 when the disc was partly decomposed. 



Perpetuation of the race is carried on by ova, as with the rest. 

 Early in April the disc is seen remarkably full, plump, and round in the 

 margin ; the intermediate space between the rays being occupied by 

 spawn. On separating a portion of the under surface, which is ve.ry thin, 

 and rather slightly crustaceous, the spawn, of vivid red, is found adher- 

 ing to it. The colour is so bright, that the under surface of the disc 

 is sensibly affected, and the space between the rays which it occupies 

 becomes ruddy. Ovoidal capsules, confusedly huddled together, compose 

 the spawn : Plate XXVII. fig. 8, where a cluster is seen as attached to 

 the skin, enlarged. Single capsules, more enlarged, whence some of the 

 ova have escaped, fig. 9. The capsular integument is so refined, that the 

 internal contents are exposed, the whole quite red. 



Specimens expanding six inches have been replete with spawn ; and 

 as late as October so plump and full, that the disc resembled a cushion 

 with the spawn also of beautiful orange-yellow, nearly mature. When 

 of such quality, they are not common. 



PLATE XXVII. 



FIG. 1. Ophiura bracteata. Mail Star-fish. 



2. Another specimen, young. 



3. Portion of a ray of fig. 5, enlarged. 



4. Disc of a specimen, enlarged. 



5. Under surface of a specimen. 



6. Portion of a ray of fig. 5, under surface, enlarged. 



7. Ova. 



8. Cluster of capsules, enlarged. 



9. Single capsules, more enlarged. 



