figures. The large oval figures exhibit their form as seen directly and sideways; the smaller ones represent the human blood-disk for the purpose of comparison; both are magnified seven hundred times in linear dimensions. The blood from which the former figures were taken was
BLOOD-DISKS OF SIREN AND OF MAN.
obtained from one of the external gills of a Siren lacertina twenty inches in length, which was then (1841) living at the Zoological Gardens, Regent’s Park. Though subjected to examination immediately, the large figure shows, in the crossing lines, traces of folds produced by the partial drying of the external capsule.
The species contained in this Order are very few, and compose but a single Family, Proteidæ; they are rather large animals, of dull sluggish manners, much resembling eels in form, with minute rudimentary feet, inhabiting the mud of
