Article III . — Zooloqical Notes. 
53 
fishes and Ophiurans. The former throw off the injured 
member in toto from the base, while the latter begin at the 
first uninjured joint and grow the new arm from its extremity. 
The writer has specimens of OpMopUolis aculeata which illus- 
trate this. 
The true anatomical nature of the bifurcating processes 
referred to above has not yet been worked out. Usually the 
ambulacral and adambulacral plates are closely involved, but 
in other cases, the new limbs start from the abactinal surface 
without reference at first to the actinal surface. A rough 
classification of the monstrosities the writer has noticed, 
might be made as follows: 
a . Monstrosities. Either of Increase or Diminution op Parts, 
Having their Origin Before the Formation op the Cal- 
careous Skeleton, i . e , in the Ovum or Gastrula. 
I. DouUe and triple monsters. Such, so far as known, 
are the result of fission, or budding in a single ovum; never 
the result of the union of two or three ova. 
II. Four or three-rayed forms ivMcli are not the result of a 
loss of a ray or rays, and six-rayed forms which are not the re- 
sult of fission nor double monsters. We do not know positively 
of any of these forms in the true starfishes, but the fact that a 
truly four-rayed Ophiuran (as the Ophioglypha Sarsii, re- 
ferred to above) is found, renders it possible that truly three, 
four, or six-rayed starfishes may occur, though, as mentioned 
above, it would be difficult to distinguish them without care- 
ful examination. The only explanation for such a case as 
that of the four-rayed Ophiuran seems to be that the loss of 
the fifth arm dates from the first appearance of the calcareous 
plates. 
b . Monstrosities, of Increase op Par ts, which are the Result 
OP Bifurcation or Budding in the Skeletal System. 
I. Six or seven-rayed forms which are the result of the 
fission to the base of one or two of the ordinary rays. Oc- 
casionally the two rays resulting from the fission from one 
are not so large as their neighbors. The writer has seen (and 
possesses), a number of instances of this class, and believes 
there is a specimen in the society’s cabinet. 
