termination of the ‘ raphe,’” 
74 THE MICROSCOPICAL NEWS. 
led to conclude, as I have stated in the introduction, that the line 
arise from internal structure.” 
But there is a peculiarity connected with the drawings of M. 
Flézel, I wish to draw attention to, viz., that there is no canal zz 
the mid-rib. If attention is drawn to the mid-rib (Fig. 29), it 
Midd 
Zw = 
AOD 
\ 
i 
Fig. 30. 
will be noticed that parts at each end of the centre puncte over- 
lap that which is supposed to be the “ canal” laying between the 
overlapping parts. Schuman, in his Hohen Tatra; Dr. Donkin, 
0 
MY 
E 
Yy 
Ss 
cy 
)0000¢ 
Fig. 32. Fig. 31. Fig. 33- 
Brit. Diat., and Prof. W. Smith, Syn. Brit. Diat., in their drawings 
of Pinnularia, have given us an intimation of such “ canals.” 
Mr. F. Kitton,* and Prof. H. L. Smith, speak of the communica- 
tion with the exterior being, “through minute apertures at the 
or median line. Also, Mr. L. Hard- 
* Science Gossip, 1878, p. 128. 
