Self-evisceration in the Asleroidea, 285 



mass of tlie cteca was protruded. By the 14tli November 

 this mass had grown to a length of 6 mm., and two other 

 arms showed protrusions of about 3 mm. in diameter; by the 

 17th the protrusions from all three arms had grown in size ; 

 and, finally, at 9 P.M. on the 18th, tiie two remaining arms 

 were ruptured and showed small protrusions. This individual 

 died the next day before self-evisceration had proceeded very 

 far. 



Is the peculiar form of self-evisceration here described 

 purposeful or morbid ? Is it in any way useful to the 

 individual or to the species, or is it to be regarded as purely 

 pathological? Tiiese are the questions suggested by the 

 observations just recorded, and it must be confessed that it 

 is not possible in the present state of our knowledge to do 

 more than hint at an answer. The fact that the operation 

 was seen to be effected by three distinct individuals of the 

 same species would warrant at least the suspicion that it may 

 be purposeful, and this suspicion gains a certain strength 

 from the many observations already on record of the occur- 

 rence of an analogous operation in another section of the 

 Echinodermata, the Holothuroid section. The manner, too, 

 in which the effect is produced in Crihella, not by a cata- 

 strophic rupture, but by a long-continued series of muscular 

 efforts, all tending towards the same end, may fairly be taken 

 as further strengthening the inference of purpose, while the 

 extrusion of the sexual products along with the viscera 

 suggests, at all events, the nature of that purpose. It is, 

 perhaps, hardly necessary to say that the word " purpose '' 

 here is not meant to imply any volitional action in the 

 human sense. It merely denotes action helpful in repro- 

 duction and dissemination of the species; and the suggestion 

 that autotomy, or self-mutilation, in the Asteroidea may be 

 purposeful in this sense is not a novel one. 



On the other hand, it may be urged in opposition to this 

 hypothesis of purposeful self-evisceration that the unnatural 

 conditions under which the living specimens were kept were 

 such as to inevitably induce a morbid state of the organism. 

 Exposed as they were to strong light for considerable periods 

 while barely covered with water, which from time to time 

 became mure or less foul as compared witii their native 

 element, the animals must necessarily have grown sickly, so 

 that tiie long-drawn-out muscular efforts which finally 

 effected the extrusion of the viscera may have been merely 

 symptoms of the approaching death of the organism. Ob- 

 viously, further study of the life-history of Cribella and of 



