142 BULLETIN: MUSEUM OF COMPARATIVE ZOOLOGY. 
twelve segments was pointed out by Brown, and was also noted in the 
older papers of Ehrenberg and Romanes. 
According to Romanes, monstrous forms of Aurelia aurita are of fre- 
quent occurrence. Abnormality consisted in multiplicity and abortion 
of parts. All cases of asymmetrical multiplication applied to litho- 
cysts, and always occurred in the same inanner. When there were nine 
instead of eight lithocysts, the extra one was always fully developed 
and in close proximity to one of the normal lithooysts. 
In symmetrical abnormalities all parts of the organism were equally 
affected. Thus all examples of multiplication extended proportionally 
to ovaries, nutritive canals, lithocysts, and tentacles, the effect being to 
increase the number while adhering to the type of the natural segments. 
In all cases the degree of abnormality was the same; e. g. 6 ovaries, 
24 unbranched radial tubes, 12 lithocysts, and a six-lobed manubrium. 
All parts and segments thus increased one third their normal number. 
Romanes calls attention to the fact that this is the same proportional 
increase as in Sarsia, with six canals, and explains it as accidental. 
Supernumerary lithocysts always occur at the ends of the faintly 
colored radial tubes, never at the ends of the darker ones. 
Segments and lobes of the manubrium may be multiplied without the 
ovaries increasing in number, Again, segments may multiply and manu- 
brium and ovaries remain normal. Processes of multiplication may not 
extend to all quadrants of the umbrella. Multiplication of parts may 
be confined to one side of the umbrella, thus doubling or tripling organs 
on one side only. 
Abnormalities usually are symmetrical. When they are not, the 
manubrium and ovaries are not affected, the segments only being multi- 
plied. Abortion of parts takes place in the same symmetrical way 
as multiplication : there may be one ovary and six segments, and three 
ovaries instead of eight and four. Segments and ovaries may also be 
reduced to one half the normal number. In these two cases the 
manubrium is not affected. ^ Abortion of parts was observed in the 
ovaries only. Partial suppression of ovaries was of frequent occurrence. 
The most prevalent case was where one ovary was smaller than the other 
three. Reduction also occurs in two alternating ovaries (i. e. opposite ). 
Sometimes three adjacent ovaries were reduced in size. 
Total suppression of one ovary was more rare. Only in twelve cases 
in thousands was total suppression of two ovaries observed: some- 
times it was two adjacent ones, and more frequently the two opposite 
ones that were absent. In one case three ovaries were absent, the 
