GREVILLE, ON DIATOMACEZ. 157 
which occur in the slide he sent me, one has nine nodules, 
the other fifteen ; while the individual I have drawn contains 
twelve, a striking instance how little dependence can be placed 
on this character. Some species whose normal number of 
nodules is four, occasionally show, as is well known, three or 
five. Professor Bailey defines the structure in the present 
Species as “ minute punctata;” but when magnified to the 
scale adopted in the accompanying illustration, it is, although 
minute, distinctly areolate to the eye. The diameter of the 
‘valve is about ‘0045”". 
Campytopiscwus, HAr. 
C. stellaius, n. sp., Grev.—Valve orbicular; canaliculi 
numerous, forming a narrow marginal band; strie radiating 
in fasciculi from the centre, and interrupted about half-way 
to the margin by an angular ridge and a row of very minute 
puncta ; diameter ‘0044”; canaliculi 10 in ‘001”. (Fig. 3.) 
In Californian guano. 
Few genera exhibit more varied sculpture than Campylo- 
discus ; as may be seen by glancing at the species figured in 
the ‘ Synopsis of the British Diatomacez,’ at those described 
by Professor Gregory in the 21st volume of the ‘ Transactions 
of the Royal Society of Edinburgh,’ and at the two very 
remarkable ones given by myself in Pl. III of the 5th volume 
of this journal. The present species differs from them all in 
the peculiar ornamentation of the centre of the valve. I 
have called the centrical radiating lines strie, as they seem 
to be of a different nature from the canaliculi which form 
the external border; it must be admitted at the same time 
that they appear to pass into the broad band intermediate 
between them and the border. As the striz proceed from 
the centre others originate at irregular intervals between 
them; and at about half-way between the centre and the 
circumference an interruption occurs in the shape of a rather 
sharp ridge, on which is disposed an irregular row of very 
minute puncta, which require careful focussing to bring out. 
The more definite strive (canaliculi?) which compose the 
intermediate broad band, are transversely undulated, giving 
them a semi-moniliform character, in this respect resembling 
the corresponding band in C. limbatus. Indeed, were the 
central radiating strize absent, the frustule would approach 
very near to that species. 
AsTERoMPHALUs, Ehr. 
‘The genus Asteromphalus was described by Ehrenberg in 
‘Berlin Monatsberichte,’ 1844, p. 198, where he defines seven 
