1070 _ General Notes. 
THE CONNECTIVE SUBSTANCE IN THE HIRUDINEA—The anatomy 
of the Hirudinea has been treated monographically by Mr. Boure. 
The following remarks on the connective substance are taker 
from his paper. 
e amount of this tissue which is developed is in direct pr 
portion to. the “limpness” of the leech. Clepsine and Nephelis 
have very little of this tissue, and are consequently relatively fim 
and rigid to the touch while living. Hzemopis and Aulostoma 
present the other extreme, remaining flabby or “limp” inal 
states of muscular contraction; while Hirudo, Trocheta, and 
Pontobdella present an intermediate condition. Pepe 
The connective substance consists of a hyaline, jelly-like mass, 
interspersed with cells. The intercellular matrix is probably 4 
veloped by ectoplastic modification of the cells lying in it The 
cells themselves undergo various modifications which take lae 
simultaneously, and to a certain extent overlap one another. Four 
principal lines of modification are mentioned. pei’ 
1. Lntoplastic metamorphosis,—Vacuolated cells and fat cells 
Vacuolation is brought about by the formation of droplets of 2 
semi-fluid substance, which give the cell a reticulate app a l 
résembling mammalian areolar tissue. Fat accumulates m Wi 
tain cells in small globules, which may remain separate or ok 
together, and form a large globule. The fat-cells do not occur it 
the Gnathobdellide. eit 
_ 2. Ectoplastic metamorphosis—Elongated ot branched eT | 
tive tissue cells occur in all the Hirudinea. It is the poo irid 
tr daana 
3. Ect-entoplastic metamorphosis —The cells develop p 
In Pontobdella, Clepsine, Piscicola, and Branchellion th 
the vascularized cells (botryoidal tissue, vaso-fibrous tissue), ™ 
cular system on the one hand, and with the sinus system Of 
other, forming ‘ botryoida ee 
_1A.G, Bourne. Contributions to the Anatomy of the Hirudinea 
Mic. Sci., xxiv, July, 1884, pp. 440. 
