AN ICHTHYOBDELLID PARASITIC ON SAND WHITING. 35 
Kovalevsky (1900) (PL 2, fig. 12 a, Sp.s.), into which open 
the ducts of the unicellular spermatophore glands called the 
B glands by Brumpb (PL 2, fig. 12, Sp.gl.). The sperma- 
tophore sac leads into the bursa — an ectodermal invagination, 
whose external opening is the male orifice (PI. 2, fig. 6). 
The muscular tunic of the terminal parts consists of a single 
layer of fibres imbricated at their ends, About four to six 
fibres complete the circuit. At the anterior end the wall 
becomes two or even three fibres thick. This circular 
musculature is continued on around the spermatophore sac, 
but here the fibres, placed two deep, are separated from those 
on either side by the ducts of the spermatophore glands. 
At the bursa the fibres decrease to a single layer, and placed 
•external to them are several longitudinal fibres, apparently 
the diverted fibres of the body-wall muscles round the male 
genital opening, which may aid in the protrusion of the bursa 
(PL 2, fig. 6). The terminal parts of the ejaculatory canals 
are lined throughout with gland cells, the ducts of which 
run radially and are directed towards the spermatophore sac 
*(P1. 2, fig. 12, Ej. t.). These ducts almost obliterate the 
lumen into which they pour their secretion. There are 
found among these ducts the small cells of the supporting 
tissue. 
The cytoplasm of these glands stains more deeply with 
haematoxylin than those of the accessory male glands outside 
"the muscular tunic. 
1'hese latter cells make up a well-developed glandular 
mass, which lies in somites 11 and 12 (Text-fig. 6, Sp.gl.). 
Each is a unicellular gland (PL 2, fig. 12, Sp. gl.) and opens 
in o the spermatophore sac. On either side this mass presents 
two lobes caused by dorso-ventrally placed muscle fibres. 
'I he development of these glands is such that they wrap 
round the terminal parts of the ejaculatory canals (PI. 2, 
fig. 12, Sp. gl.). 
The secretion space of each cell is generally filled with 
numerous granular eosin-staining particles, as are also the 
•ducts opening into the spermatophore sac. 
