318 J- Beard 



are most numerous. The occuirence was only observed twice or thrice 

 in several hundred Comatula^ and it is very Gurions, that, if the 

 dorsicolous forms can move about at will, as Wheeler asserts 

 pag. 266 foot-note), these two or three specimeus should have turned 

 out to be hermaphrodite, while all the other true dorsicolous speci- 

 mens were pure males. 



It would be of interest to learn, upon what observations Wheeler 

 bases his conclusion, that the dorsicolous forms can shift their posi- 

 tion. Is it, again, an assumption rendered necessary under his 

 hypothetical scheme of the life-history of the animai? If it be based 

 on Observation, its importance, surely, entitles it to a better position 

 than in a small foot-note of some two lines! 



It cannot be denied that these forms do alter their position, but 

 all my experiences of them at Naples convinced me that, once seated, 

 they remain in one position. 



Experiments were made in 1884 to test this very point. Coma- 

 tulse, infested with large hermaphrodites hearing dorsicolous forms, 

 were kept alive for six weeks and longer and were examined from 

 time to time. Never once was the slightest evidence of change of 

 ])Osition noticed. 



But this iixity of position is rendered far more certain by another 

 circumstance, which would appear to have escaped Wheeler's notice. 

 The dorsicolous forms insert their hooked seta3 deeply into the tissues 

 of the hermaphrodite, and, whereas the latter can be removed from 

 its host with but slight damage, or none, to these setae, the dorsi- 

 colous forms are so tirmly affixed to the hermaphrodites, that the two 

 can only be separated with loss of many at least of the set^e of the 

 former. 



On pag. 267 Wheeler comments on the difficulty, which the 

 young may be supposed to experience in first fixing themselves to 

 the arms or disc of a Comatula^ and recognises in the dorsal inte- 

 gument of a hermaphrodite a place of attachment easier of attain- 

 ment and favourable for respiratory and nutritive purposes. 



It has to be proved that the back of a hermaphrodite is softer 

 than the disc of a Comatula^ and, if there be the differeuce and ad- 

 vantages claimed by Wheeler, it is enigmatical why the dorsicolous 

 forms are so rare, why the occurrence of two such on one herma- 

 phrodite was only encountered by me once, and, in short, why the 

 backs of the hermaphrodites do not bristle with such >young« indi- 

 viduals. 



