Lauder^ on Marine Diatomac€<s. 
77 
and even the sporangium differs very mncli in shape in appa- 
rent varieties. 
The best division of the species is into those having dotted 
and those having spinous awns, the members of each group 
generally having other characters in common. 
^ Awns beaded, the beads or dots passing round the 
awns in a spiral manner. 
Ch(Rtoceros socialis, n. sp. Filaments slender, aggregated, 
embedded in gelatine, with wavy, spirally dotted awns, some 
of which are more elongated, and converge to a common 
centre (fig. 1). Hong Kong. 
This is the smallest species I have seen. By the aggrega- 
tion of the filaments in gelatine, it forms roundish, flattened 
fronds. Frustules quadrate, with an awn from a little within 
each angle, one of them being more elongated, varying in 
length, according to the distance of the frustules, to a com- 
mon centre, to which the elongated awns converge ; many 
frustules, however, occur, in which the awns are not thus 
connected ; side view oval. 
C. ciliafa, n. sp. Filaments elongated, spiral, with oval 
fenestrae and short awns ; sporangium with smooth, convex 
valves, surrounded by setae arising from the margins of the 
connecting zone (fig. 2). Hong Kong. 
Filaments composed of 100 frustules or more, which have 
concave sides, forming interstitial, oval fenestrse, and a stout 
awn from each angle, recurved away from the centre of the 
spire. About November, in many of the frustules, a highly 
reflective Goniothecium-like body or sporangium appears. 
Side view of valve broadly oval. Breadth of frustule, rinro'' '> 
length of awn, 
C. Lauderij n. sp., Balfs. Filaments with quadrate frus- 
tules, narrow-oblong fenestrae, slightly and gradually con- 
stricted at the middle, and long awns ; sporangia with very 
unequal, spinous valves, the larger one capitate (fig. 4) . Hong 
Kong. 
About the middle of April, and shortly previous to the disap- 
pearance of the filaments, sporangia are seen, in which the 
larger valve is capitate, hirsute, and connected to the hoop 
by a broad, smooth neck. The smaller conical valve is fur- 
nished with spines, or a delicate plicated membrane resem- 
bling spines. I think the latter, because there is no trace of 
this lower part with membrane attached after boiling in acid. 
There is also a fine plicated membrane attached to the mar- 
gins of the hoop). I think it is a large variety without 
the constricted neck. Breadth of a, -irhr''- 
VOL. XII. / 
