343 
C. elliptica. Sm. Not so plentiful as the above species, but 
usually accompanying it. 
C. apiculata. Sm. Rare — only in the Whissonsett gathering. 
Genus Amphipleura Kutzing. 
A. pellucipa. Kiitz. Not unfrequently in the Ormesby gather- 
ings, but rare in other localities. 
Family V— N1TZSC1II/E. 
Genus Denticula Kutzing. 
D. Kutzinqii var. major. (Grunow.) Ormesby and Horning. 
D. sinuata. (Sm.) Common on moss growing at the base of 
willows, Osier Car, Heigham. 
Genus Nitzschia Hassell. 
N. sigmoidea. (Sm.) Copious in a ditch running into Ormesby 
Broad ; not frequent in gatherings from other localities. 
N. sigma. (Sm.) Very frequent in salt-water ditches; a form with 
a very coarse strim occurs in a ditch in Burgh. 
N. amphioxys. (Sm.) Plentiful in moss from Osier Car, Heigham; 
rare in soil attached to roots of Equisetum, growing near 
the river, at Hellesdon. Mr. Norman in his “ List of 
Piatomaceie occurring in the neighbourhood of Hull,” says, 
he found it frequently in moss from cottage roofs. 
N. vivax. (Sm.) Frequent with preceding species in the 
Heigham moss. This is usually considered a brackish- 
water form, but the water in this locality is quite free 
from salt. 
N. hyalin a. (Greg.) Hunstanton sands. 
N. dubia. (Sm.) Breydon, North River; salt-water ditches, 
Yarmouth, Veils, Blakeney. 
N. obtusa. (Sm.) Rare — in the Whissonsett and Flordon 
gatherings. 
N. minutissim a. (Sm.) Moss, Osier Car, Heigham ; not un- 
frequent on wet walls. 
N. linearis. (Sm.) Whissonsett, Ormesby, and Horning. 
