84 CLASS GASTEROPODA. 
The branchiz form but a single range along the left side of 
the roof of the branchial cavity. The right side is occupied 
by the rectum and the spermatic canal, which also transmits 
the ova. There is no penis, the animal fecundating itself. 
The species are numerous, but not very distinct. Linnzus 
left them among the serpule. 
The VERMILI, also left by M. de Lamarck near the ser- 
pul, are similar to the vermeti. 
MaeiLus, Monty. 
The magili have a longitudinally carinated tube, which is 
at first regularly spiral, and then extends itself in a line more 
or less straight. Although the animal is unknown it is 
highly probable that it should be placed near the vermeti. 
The 
SILIQUARIA, Brug., 
Resembles Vermetus in the head, the position of the opercu- 
lum, and in the tubular and irregular shell; but there isa 
fissure on the whole length of this shell which follows its con- 
tour, and which corresponds to a similar cleft in that part of 
the mantle which covers the branchial cavity. Along the 
whole side of this cleft is a branchial comb, composed of nu- 
merous loose and tabular-like lamellae. Linnzus left them 
with the serpulz, and till very lately they were considered as 
belonging to the class of the annelides. 
