18 
Ctreville_, on New Diatoms. 
planation^ I tliought I would carefully -watch a spider during 
tlie operation, when, with only a pocket lensj I could dis= 
tinctly see that the viscid lines^ as first drawn from the 
abdomen were not dotted. 
On a careful examination with a microscope, which I took 
into the garden; the thread at first appeared only slightly thicker 
than an ungummed line, but after a very short time undula- 
tions appeared, and subsequently, at the most regular dis- 
tances, the \dscid matter formed into alternating large and 
small globules. 
The whole process is such a beautiful illustration of molecu- 
lar attraction, which Mr. Rainey has been so patiently and 
profoundly working out with regard to the highest organic 
structures, that I thought this simple example might interest 
some of our members. The cold weather has, of course, driven 
away these spiders till next autumn, at least, but the same 
result can easily be obtained artificially. 
Descriptions of New and Rare Diatoms. Series V. 
By R, K. Greville, LL.D., F.R.S.E., &c. 
(Read Dec. lltli, 1861.) 
Having recently been presented by my friend. Dr. Macrae, 
Presidency Surgeon, Calcutta, with a considerable series of 
slides of diatoms collected in Ceylon and on other parts of 
the Indian coast, I hasten to lay before the Society a notice 
of some of the more interesting species contained in them. 
I have not, however, exhausted the materials so kindly placed 
in my hands, and must reserve a description of other novelties, 
as well as any general observations I may have to make on 
the entire collection, for a future communication. Dr. 
Macrae has returned to India with the intention of taking 
every opportunity of prosecuting his diatomical researches, 
and we may confidently anticipate many interesting dis- 
coveries in a field comparatively unexplored. 
surirella, 
Surirella fastuosa, Ehr. — Elliptic, with rounded ends, 
and rather distant cost^e, dilated towards the margin ; median 
space more or less lanceolate, enclosed within a line of ex- 
tremely short transverse stride. Length '0025 to '0074". 
(PL III, fig. 1.) 
