34 Verm. 
VERMES. 
Whitman (2). Clepsine plana : this species may or may not be iden- 
tical with C. parasitica of Say and Verrill. Latter has no value as a 
species. Author draws attention to the fact that metamerism in the 
leeches has undergone modification in two opposite directions. Variation 
by centripetal reduction of the number of rings is universal ; variation by 
multiplication of rings, characterises, as a rule, only the higher forms — 
Hirudo , Nephelis, &c. Hirudo swims, while Clepsine creeps. 
Clepsine carinata = ((?. papillifera , var. carinata , Verrill.) Whit- 
man (1). 
Biology. 
M&GNIN (S). 
Whitman (1) has made observations on the copulation of Clepsine 
plana and C. carinata. The spermatophores are placed by one individual 
on any point whatever of the surface of another, usually the dorsal sur- 
face. The spermatozoa are then injected through the body-wall. How 
the passage through the tissues is effected is left undecided. Author has 
followed the track of the spermatozoa from the point of penetration to 
the coelomic cavity in which the ovaries lie. This mode of impregnation 
was discovered by Lang for Turbellaria, in 1882, and has since been 
described by Plate for Rotifera , and Harmer for Dinophilus. Among 
leeches, it possibly occurs in all the Rhynchobdellidce. 
Histology, Physiology. 
Apathy (8). Bolsius (1, 2) [see below, “ Morphology ”]. 
CuriNOT. Biedermann. Nervous system of Hirudo medioinalis , pp. 
484-449. 
Retzius (1). Nervous system of A ulastomum gulo and Hirudo medi - 
cinalis , pp. 13-28, Taf. vi-x. 
Roiide. Nervous system of Aulastomum gulo and Pontobdella muricata. 
Each ganglion, consisting of six distinct groups of ganglion-cells, contains 
also six remarkable supporting cells (Stutzzellen) described for first time. 
Each supporting cell gives out from all points of its surface fibrous pro- 
cesses, which envelope a corresponding group of ganglion colls. The 
ganglion cells of the central nervous system are all unipolar ; but there 
are a number of very large peripheral ganglion cells in Hirudinea which 
are multipolar. 
Embryology, Morphology. 
Apathy (2). Bergh (see below). Burger (1) (see below). 
Bergh finds that in Clepsine where the primary epidermis is continued 
as the definitive epidermis, the four rows of cells which form on each 
side the middle layer of the germ-band (i.e., lying between epidermis 
and the inner mesodermic layer) develop as follows The median series 
