The Sexual Conditions of Myzostoma glabrum (F. S. Leuckart). 317 



expect to find at least as mauy hermaphrodites as males among- the 

 stages of 66 — 93 sections«. 



Why tliis sbould be so, is a complete puzzle. The stages of 

 66 — 93 sections were dorsicolous forms from hermaphrodites, and 

 the picking of these bad notbing to do witb the making up of the 

 table, sbowing the relative occurrence of bermapbrodite and dorsi- 

 colous formst Perbaps, it is supposed, that ali the small berma- 

 pbrodites found were used and sectioned, but tbis was not the case. 

 Whilst ali the largest males were taken, only samples of the disc- 

 forms were made use of, but such as formed a continuous series. 

 I believe I bave stili several very small hermapbrodites, i. e. under 

 1 mra, unsectioned. If anyone believe that be can prove tbese disc- 

 forms to be pure males, in wbicb eggs are absent, as they ougbt to 

 be on Wheeler's view, be is quite welcome to tbem. 



I think it has been shown by my former table of relative occurrences 

 of the two forms — and ali my experiences contìrm tbis result — that 

 the dorsicolous forms occur most frequently, when only one large 

 disc-individual is present, that they are very rarely met witb wbere 

 several large disc-forms infest one individuai, and that, at a very 

 favourable estimate, there are not more than 10 dorsicolous forms to 

 every 50 large disc-specimens, i. e. hermaphrodites. 



If the dorsicolous forms were merely young hermaphrodites, one 

 wouid expect, that they would be at least as numerous as these, 

 for are not young forms of animals usually more numerous than 

 grown-up individuals? Tbis arguraent is not efifected by Wheeler's 

 assumption — for it is notbing but a supposition — that the herma- 

 phrodites live a long time, or by that relating to the destruction of 

 the earliest stages. When an individuai becomes dorsicolous it is 

 far beyond the earliest and criticai stages, and is in a position of 

 comparative security. 



Paragraph 6 relates to the rare occurrence of forms on the 

 side-wall of a bermapbrodite. I bave already discussed tbis point 

 (pag. 309), and would only add, that the relatively small area around 

 the mouth available on one Comatula for fixation of the parasites 

 renders sucb an act on the part of future hermaphrodites not unlikely. 



I bave no recoUection of ever baving observed tbis phenomenon, 

 wbere only one large bermapbrodite occupied the disc, and it is, as 

 the published table sbows, in such cases, that the dorsicolous forms 



1 This table was reaìly made 10 years earlier in Naples. 



