160 
Norman^ 07i Dlatomacecje. 
P. tenuissimum, Sm. — Rare. Not imfrequeiit in a large pool 
of salt water near the Dock, Grimsby. 
P. littorale, Sm. — Rare. — Mixed with P. angulatum. Shores 
of the Humber, between Grimsby and Stallingbro\ 
P. Hippocampus, Sm. — Very frequent in salt and brackish 
water. Pure on Humber Banks. Garrison Moat. 
River Hull. Tetney. Ditch near River Hull^ above 
Stoneferry. 
P. attenuatum, Sm. — Very abundant in fresh water. Spring 
Ditch. Pure at Haltenprice. Cottingham. Nettleton. 
Risby Pond. Newbald. Frequent in Hornsea Peat. 
Market Weighton Canal. Wawne. 
P. attenuatum, Sm. Var j3. — Frequent in fresh water. Reser- 
voir Waterworks. Wawne, &c. 
P. lacustre, Sm. — Abundant in fresh water. River Hull. 
Cottingham. Risby Pond. Ripley. Harrowgate. 
Haltenprice. Hornsea Peat. Beverley. Market 
Weighton Canal. 
P. Spencerii, Sm. — Frequent in fresh water. Spring Ditch. 
Hornsea Meer. Wawne. Risby Pond. Clay Pit, 
Nettleton, very good. Haltenprice. Hornsea Peat 
Deposit. 
P. Parkerii, Harr. — Copious in a fresh- water gathering from 
Thornton-le-Moor. 
ToxoNiDEA, Donkin. 
T. insignis, Donk. — Rare in Ascidian gatherings. 
T. undulata. Nor. M. S. — Very rare in an Ascidian gathering. 
Synedra, Ehrenbergi 
B. pulchella, Kiitz. — Not common. Salt and brackish water. 
Humber Banks. Reservoir Waterworks. 
S. gracilis, Kiitz. — Not unfrequent in brackish ditches. 
North Humber Bank. 
S. acicularis, Sm. — Frequent in salt and brackish water. 
Humber Banks. Tetney, in large pool of water near 
the Lock. 
S. minutissima, Kiitz. — Not common. Frequent in a gather- 
ing from a ditch between Newland Toll Bar and Stone- 
ferry. Thornton-le-Moor. 
S. salina, Sm. — Rare. Brackish water. Market Weighton 
Canal. 
S. radians. Sm. — Abundant in almost every fresh-water 
gathering. Spring Ditch. Risby Pond. River Der- 
went. Cottingham. Newbald. Wawne. Reservoir 
Waterworks. 
