310 
PROFESSOR E. RAY LANKESTER, 
XXVI, fig. 4), and an extreme modification in the opposite 
direction, which appears under the form of botryoidal tissue 
(PL XXVIII, fig. 15) called hepatic by Brandt, mistaken 
for cutaneous glands by Leuckart, and compared to the fatty 
body of insects by Leydig. I propose to term this ento- 
plastic form of skeleto-trophic tissue — which has so Protean 
a character — vaso-fibrous tissue.” 
The connectim jelly of the Leech . — This tissue may be 
best studied on perfectly fresh samples, which are to be 
obtained by teasing any portion of the muscular paren- 
chyma which intervenes between the integument and the 
wall of the alimentary canal. 
It consists of a jelly-like matrix, in which are embedded nu- 
merous branched corpuscles, varying in diameter from t^-o tfi 
to the of an inch.i The branches of the corpuscles are 
drawn out into very fine processes, and finally are lost in 
exceedingly delicate filaments, which permeate the jelly in 
every direction. Treatment with nitrate of silver gives the 
usual result observed with such tissues, viz. a dark staining 
of the matrix, whilst the corpuscles are left as clear spaces. 
The corpuscles vary in size and in colour in different 
specimens of the tissue. When young they are small and 
contain a few highly refringent granules of large and regu- 
lar size. Older tracts of the tissue show corpuscles of larger 
size, the granules within them being very numerous, of large 
size, and similar to one another ; the granules are in these 
older cells of a decided brown or straw colour. In some 
parts the corpuscles may be found to be very much elongated, 
and suggests the possibility of a transition from the ecto- 
plastic connective jelly to the entoplastic vaso-fibrous tissue. 
Even in perfectly fresh corpuscles of the connective jelly a 
clear space amongst the granules may be observed, which 
indicates the nucleus. Treatment with osmic acid, followed 
by picro-carmine (on the glass-slip, whilst under a cover- 
glass, in the manner recommended by Banvier), gives two 
interesting results. First, the granules become very much 
stained by the osmic acid, and, secondly, the nucleus, but no 
other part of the corpuscle, becomes coloured by the carmine 
(PI. XXyil, fig. 2).‘ 
The highly refringent granules of these corpuscles are 
very characteristic on account of their largeness, their colour, 
and their regularity of form and size. They are not simply 
fatty matter, since they are not dissolved by ether. They 
arc possibly of the same chemical nature as the very much 
* A very similar tissue oeeurs beueatli the epidermis of Sipunculus 
nudus, having, however, a more cartilaginoid matrix. 
