Walker-Arnott^ on Campylodiscus Hodgsonii. 85 
bably, apart from the broad distinctions of calm or tempest, 
which regulate the appearance or disappearance of many of 
the minute animal organisms from the surface^ sometimes at 
a moment^s notice ; and I cite the circumstance in order to 
warn others, who may perchance go down into the sea in 
ships/^ never to lose an opportunity of capturing any crea- 
tures that present themselves, however abundant they may 
appear to be, for whilst one cast of the net may contain a 
myriad, the next may be drawn blank and unfruitful. 
In conclusion I would observe that it is my intention to 
work out as far as possible the Diatomaceae and Desmidiacese 
at my command. The other families I shall not venture to 
approach ; but any specimens, drawings, or information it is 
in my power to supply to those gentlemen who direct their 
labours towards them, I can only say shall be most cheerfully 
placed at their disposal. 
Note on Campylodiscus Hodgsonii. By G. A. Walker- 
Arnott, LL.D. Communicated by Mr. F. C. S. Roper, 
F.L.S. &c. 
(Read April 20ih, 1858.) 
On examining with some attention your slide of Campy- 
lodiscus Hodgsonii from Lyme Regis, and comparing it with 
others in my possession, I find — 
" 1. That your specimen is the same as what I have from 
the River Orwell, contained in a slide from Professor Smith, 
named C. Hodgsonii, and marked. Collected by J. Hodgson, 
Esq., August, 1850." 
" 2. That it is the same as one I have from Carrickfergus. 
^' 3. That it is the same as two frustules I have found in a 
gathering from Ipswich, obtained several years ago by the 
late Mr. Wigham, of Norwich. 
" 4. That it is the same as one frustule (one of four marked 
ones) contained in a slide from Poole Bay, of September, 
^ 1852, from the late Professor Smith. 
'^5. That it is the same as the C. eximius of Dr. Gregory. 
All these agree with the large state of the species, fig. 53, of 
Smith's 1st volume. 
^' I also find that the small state of C. Hodgsonii is not well 
represented in Professor Smith's book, fig. 53 a, there being 
no moniliform lines, but canaliculi on the central part or disk . 
This small state I find (from one to three frustules in every 
