1864. ]} DR. J. E. GRAY ON MYRIOSTEON HIGGINSII. 163 
the other behind; and the fur, as I have already mentioned, lying 
as smoothly when stroked from tail to head as it does when turned 
in the natural direction, enables him to retreat tail first into his hole 
as easily as he could go adopting his usual mode of progression. 
2. Notice or A Portion or A New Form or Animat (Myrt- 
OSTEON HIGGINSII), PROBABLY INDICATING A New Group 
or EcuinoperMaTA. By Dr. Joun Enwarp Gray, F.R.S., 
F.L.S., ETC. 
Four or five years ago the Rev. H. H. Higgins, of Liverpool, pur- 
chased in London a specimen which was shown at the time to seve- 
ral naturalists, and was pronounced by some to be the tail of a Ray 
(perhaps of Urogymnus africanus) ; and this determination seems to 
have been so far satisfactory that up to this period it has not been 
further described. 
During a recent visit to the Free Museum at Liverpool the spe- 
cimen attracted my attention, and Mr. Moore, the intelligent Curator 
of that institution, placed it in my hands for examination and deter- 
mination ; and the trustees of that institution have most kindly pre- 
sented it to the British Museum. I was soon satisfied that it could 
not be the tail of a Ray, nor, indeed, a part of any vertebrated 
animal. The outer surface (and, indeed, the whole substance) is 
made up of a number of calcareous concretions, united together by 
anastomosing processes placed on the outside of an internal rather 
thick coat formed of longitudinal fibres, which is rather hard and 
firm when dry. The interior of the tapering tube is quite empty, 
without any septa or other divisions. 
It is very unlike the skin of a cartilaginous fish, which is always 
a good firm skin, more or less studded with hard, imbedded, bony 
seales or processes, or the case of an Ostracion, which is formed of 
cartilaginous or horny tesseree. The rounded surface, which has been 
regarded as the upper surface of the tail, is pierced with two series 
of small, rather unequal-sized, oblong holes, which look very like 
irregular ambulacra for the passage of the feet or tentacles of the 
animal which formed the body, as in the case of the Star-fishes ; 
and yet, at the same time, these holes are very different from the 
ambulacral pores of those animals, which are always in pairs and 
surrounded by some special ossicles. Besides the holes on the 
rounded or upper edge, there are a few similar perforations, but 
smaller in size, on the sides of the thicker part of the tube. 
The entire surface of the external skeleton is cribellated with 
small pores between the ossicles, as is the case with many Asteriade 
and Echinide. This porousness of the surface induced one of the na- 
turalists to whom it was shown to suggest that it might be the shell 
of a gigantic Foraminifer, or the coral of one of the Polyzoa; but 
this opinion cannot be entertained, as the pores are very unlike the 
pores of those animals, and the large continuous internal cavity, which 
has been evidently occupied by some part of a larger animal, is totally 
opposed to such a theory. 
