116 REPORT—1868. 
Moreover that almost every intermediate condition between complete diphyodont 
and simple monophyodont dentition existed, citing especially the Sirenia, Elephants, 
Rodents, and Marsupials. He then, by the aid of diagrams, showed particularly 
two modes of transition between monophyodont and diphyodont dentition—one in 
which the number of teeth changed was reduced to a single one on each side of 
each jaw, as in Marsupials, and the other in which the first set of teeth, retaining 
their full number, were reduced to mere functionless rudiments, and even disap- 
pearing before birth, as in the case of the seals, especially the great Elephant seal. 
These observations showed that the terms “monophyodont” and ‘‘diphyodont,” 
though useful additions to our language, as means of indicating briefly certain 
physiological conditions, have not, as applied to the mammalian class, precisely the 
same significance that their author originally attributed to them. 
The classification and special homologies of the teeth of the heterodont mammals 
was next discussed. Certain generalizations as to the prevailing number of each 
kind of teeth in different groups of animals were sustained, but deviations were 
shown from some of the rules laid down, such as that when the premolars fall short 
of the typical number, the absent ones are from the fore part of the series. The 
general inference was, that, although in the main the system of notation of the 
mammalian teeth, proposed by Professor Owen, was a great advance upon any one 
previously advocated, we must hesitate before adopting it as final and complete in 
all its details, and need not relax in our endeavour to discover some more certain 
methods of determination. 
On the Anatomy of the Carinaria Mediterranea. By Roserr Garner, 7.1.8. 
In this paper the author gave the anatomy of a male and female specimen, with- 
out any reference to the descriptions of previous observers, as Delle Chiaje, Verany, 
and others. The cylindrical form of the animal, finned tail, curiously modified 
molluscan foot, and the viscera excluded, as it were, by hernia, from the body, and 
covered by the delicate shell, are tolerably well known. The envelope or tegument, 
though tuberculated or spiny, as well as covered with small and larger granulated 
opacities, and mottled with brown, is so diaphanous that the stomach and first 
part of the intestine can be seen through it. A second inner coat is composed of 
a beautiful network of muscular fibres, but the tail has fascicles only from this coat. 
The foot or abdominal fin, carried, however, upwards as the animal swims, is neatly 
reticulate and tinged with rose-colour, and has a little suctorial disk on its posterior 
edge. The sea-water is admitted into the body of the animal by a pore behind this 
fin. The animal has a retractile trunk, and tentacles with well-developed eyes. 
Within the muscular sac, besides the stomach and first part of the intestine, is little 
else but the buccal apparatus, two salivary glands opening near the commencement 
of the gullet, the brain and pedal ganglion, and aorta. The ribbon of lingual teeth 
is pretty simple—a tricuspate broad tooth in the centre, a large hook on each side 
laterally, and between the two another piece with a long and short point. These 
teeth dissolve in boiling nitric acid, and consequently are not siliceous. The buccal 
box itself is ample, with six or seven pairs of extraneous muscles, besides powerful 
intrinsic ones attached to its cartilaginous basis. The stomach, which immediately 
succeeds, contained remains of Pteropoda (small conical Cleodore), of small Cepha- 
lopoda, and portions of the lingual ribbons of its own species; also beautiful discous 
and other Diatoms. The bulk of the viscera are covered by the shell, which also 
has attached to it the muscles, with much the same disposition as is seen in a Pa- 
tella. The intestine entering this nucleus makes many conyolutions at the front 
of the shell, and then opens on the right side under the margin of the shell and 
mantle. The brain is supra-cesophageal, and is seen to consist of three amalgamated 
pairs of ganglia. Of course it gives nerves to the eyes and feelers close at hand, 
the former having large lenses covered by the transparent skin ; also to the mouth, 
and is connected with two little ganglia situated on the buccal box. Four nerves 
go backwards from the lateral and posterior parts of the brain, two forming a lobed 
ganglion near the abdominal fin, supplying it and the tail, and two rising towards 
the viscera, forming a ganglion at the root of the branchie, There are also two 
neryous enlargements near the pylorus, and auditory sacs on the pedal ganglion. 
