52 Bulletin of Natural History Society. 
Teratology, Many monstrosities occur in this species. 
The most common is that in which six rays are found, and 
we have every variation from cases in which there are five 
rays, one of which is bifurcated at tip, down through different 
degrees of division of the split limb to cases in which there 
are six perfect rays. This shows one way in which the six. 
rayed state is brought about. But others are found, it is 
said (the present writer has noticed none), in which with six, 
or sometimes even more rays, are found two madreporic plates 
(or one formed by fusion of two), and two stone canals. Such 
cases are considered by Giard to be true double monsters, 
comparable with double fishes and the like. The subject 
is discussed in Annals and Mag. Nat. Hist., 5th ser,, L, 1878, 
pp. 259-5^60, translated from Comptes Rendu^s of Nov, 19, 
1877, p. 973. 
Again, in Mag. Nat. Hist., 2nd ser., IV., 1846, p. 34, J 
Couch describes an Asterias glacialis, now considered to be 
A. ruhens, which had eight rays and three madreporic plates. 
It is not impossible that it may have been a triple monster, 
the result of fission or budding in a single ovum. 
The numerous cases in which there are four, three, two or 
even but one ray present are not ordinarily monstrosities, but 
the result of accident, and inspection will usually show that 
the missing rays are being replaced. A case is on record 
(Proc. Nat, Hist. Soc. of Glasgow, I., p. 41) in which one of 
the limbs growing to replace a lost one, was bifurcated. Yet 
cases of four and three rays would be monstrosities when 
these are the maximum number that the individual has had 
in its development. Such cases are likely to be confounded 
with those in which a limb has been recently lost, and are^ 
therefore, likely to escape notice. Yet, such probably do 
occur in the true starfishes, as they certainly do in the Ophi- 
urans, in which, on account of the infiexibility of the disk, 
the true number of arms is easily counted. The writer has a 
fine specimen of OpMoglyjAia Sarsii with four rays, which are 
placed at exactly equal intervals around the disk. There is a 
difference' also, it maybe said in passing, in the method of 
proceeding to repair a damaged arm, between the true star- 
