CEEA.TA OF DENDRONOTUS. 357 



of the nerves and their origiji from the different ganglia. 

 With the higher powers of the microscope it is also 

 possible to make out the nerve fibres themselves, cut 

 transversely, in each of the sections. I have thus been 

 enabled to determine to my complete satisfaction that 

 there is a junction of nerves and not merely a running 

 alongside or juxtaposition without the fibres of the pedal 

 branch mingling with those of the pleural branch. In 

 order to demonstrate this I give drawings made with a 

 Zeiss objective D from the various sections concerned in 

 this anastomosis of the two nerves. In PL XV., figs. 2, 

 3, and 4 are made from three consecutive sections, and 

 show the origin of the branch from the dorsal pedal nerve. 

 Fig. 3 is made from the section through the point of 

 origin ; fig. 2 just anterior to it ; and fig. 4 just posterior 

 to it. In these sections the transversely cut fibres with 

 the nerve sheath or perineurium can be distinctly seen. 



Fig. 2 shows two nerves (a and h), lying in the coelomic 

 cavity {coe), with part of the wall of the oesophagus (ce). 

 The nerve marked a is the epipodial nerve originating 

 from the pleural ganglia ; the nerve marked h is the dorsal 

 pedal nerve arising from the dorsal aspect of the pedal 

 ganglia. For the sake of distinctness other structures in 

 the neighbourhood are left out. 



Fig. 3, taken from the next section succeeding fig. 2, 

 shows a constriction appearing in h, with the perineurium 

 or investing sheath extending inwards from the con- 

 striction, suggesting the beginning of the branch nerve c 

 which in the succeeding section, shown in fig. 4, is seen 

 separated by a complete sheath. Here although the 

 nerve h and its branch c are not actually apart, still the 

 fibres are, and the succeeding four sections show this 

 branch gradually getting more distant from h, and rising 

 towards a. 



