The Sexual Phases of Myzostoma. 
267 
tachment left between the young hermaphrodites and Beard's com- 
plemental males. 
V. Graff believed the attachment of the young Myzostomes 
to the outer or dorsal region of the larger specimeos to be due 
to a desire to get as near as possible to the food current enter- 
ing the Crinoid's mouth. This view was rejected by Beard on 
what appear to me to be very insuffìcient grounds. While I accept 
V. Graff's view as probably correct, I believe that there are also 
other causes which induce the young to settle on the backs of the 
old specimens. I deem it very probable that the young, when they 
give up their pelagic life, may find it difficult to insert their small 
and weak parapodial hooks into the tough skin of the Crinoid's disc 
and consequently choose the softer dorsal integument of the older 
Myzostomes. Furth ermore it is not improbable that the rapid cur- 
rent-producing movement of the cilia covering the backs of the old 
hermaphrodites may favor the respiratory and nutritive conditions in 
the young individuals. 
7) Beard's remarks about the organs which I bave called the 
ovaries (Nansen's »problematic organs«) resolve themselves into so 
many purely gratuitous assertions, and they show very clearly that 
he has never studied these organs at ali carefully. At page 402 
(foot note) he says of them: «these may quite possibly be rudimen- 
tary or ,accessory^ testes in the male«. Why it should be necessary 
to invoke even the possibility of their beiug »accessory« testes is far 
from apparent, except for the purpose of throwing doubt on my Inter- 
pretation. And bere I would dispose of the notion of their being 
rudimental organs, a view which Beard evidently appropriated from 
Nansen, and found very useful in conducting bis argument. The only 
grounds that can be brought forward to indicate a «rudimental« or 
«vestigial« character are the relati vely small size of the organs and 
of their component cells, Their small size is no proof that they are 
not ovaries, as a comparison with the Oligochaeta shows. As well 
might we regard as rudimental the two small bodies which occur 
in but one segment of the earthworm, and the ovarian nature of 
which has never been doubted, owing to the fact that the ova do 
not leave these organs tili they are large enough to be recognized 
as ovai, if they broke away from the ovary in a younger stage 
1 Miss Katharine Foot has kindly sent me some specimens of earth- 
worm ovaries with measurements of the worms from which they were taken. 
