Rose, on Parasitic Borings in Fossil Fish-scales. 9 
borings, and so greatly resembling those in the last-examined 
scale (fig. 3), I must, therefore, consider its parasite but a 
variety of the one which infested that scale. This specimen 
is represented by fig. 4 ; the decussating lines shown are 
probably markings peculiar to that kind of scale. 
Pursuing this interesting inquiry, I next took a scale found 
in the shale of the Kimmeridge clay, and in it I met with 
another form of the parasitic workings ; for, in the first 
place, they are of a larger calibre, and their form is more 
decidedly dichotomous. See fig. 5. The figures given from 
this scale clearly show that the parasite inhabited layers 
deeper than the external one ; indeed, this circumstance was 
manifest in some of my first specimens. With the view 
of determining whether similar depredations are committed 
upon the scales of living fishes, I have carefully examined 
numerous scales of several different marine and fresh-water 
fishes ; and I have not met with a vestige of borings of any 
kind in a single instance. 
To what form of organism, vegetable or animal, are we to 
attribute these remarkable operations ? We are, I am aware, 
fully cognizant of the invasion of recent corals, shells, and 
bones, by boring sponges (Clionae) and Confervas.* But those 
intruders, although comparatively small, have their workings 
in most cases visible to the unassisted eye ; whereas, in the 
instances which I have brought before you, most of them 
require a magnifying power of l-4th to enable us to trace 
their course with any degree of distinctness. In my first 
specimen (fig. 1, Plate I.), the borings of which I took great 
pains to measure, I estimated their calibre at about one 
2-lOOOth to 4-lOOOth of an inch. 
I learn from Mr. Morris's paper, before referred to, that 
M. von Hagenow has, under the name of Talpina, " arranged 
certain problematical branching bodies, which traverse the 
spathose guard of the Belemnite, and whose position in the 
animal kingdom has not been defined, whether as belonging 
to the Annelides or to the boring-sponges." From the mi- 
nuteness of the agent effecting the borings within the fish- 
scales, I am more disposed to attribute them to the operations 
of infusorial parasites, rather than to the growth of sponges or 
confervae ; particularly when I consider that the ocean de- 
positing the calcareous mud must have been the habitat of 
myriads of Infusoria of infinitesimal calibre, f 
* See Professor Quekett's Lectures on the Histology of Animals, vol. ii, 
pp. 42, 153, &c. 
t Since reading the above paper, I have found abundance of borings in 
a scale from the mud of the river Oran, in Algeria. — C. B. E. 
