Aberdeenshire, frequent. Dr. Dickie. Lough Mourne and Peterhead Deposits
Preiniiay Peat. Dolgelly Earth. Marl, Co. Down. Cantyre Peat.
Lough Island-Reayey Deposit. (Little Palls, N. Y., Oregon, and Nova Scotia;
hew Zealand.) /3. Lough Neagli, Dr. Dickie.
Plate XXIII. 219. Frustules with endochrome. Frontispiece, fig. CCXIX.
2. Cocconema cymbiforme, Ehr. F.V. linear-oblong; V. narrow,
concave margin scarcely inflated; striæ moniliform, 21 i n -001".
Length -0016" to -0032". v.v.
Ehr. Inf. xix. 8. Kiitz. Bacill. vi. 12. Hass. Alg. ci. 2.
Fresh water : not so frequent as the last, and scarcely distinct from it.
Near Vareham, Apr. 1848; Lewes, May 1851, W.Sm. Near Bristol,
Mr Thwaites. _ Wray Lancashire, Mr. G. Smith. Lough Mourne and
I eterhead Deposits. Marl, Co. Down. Cantyre Peat.
Plate XXIII. 220.
3. Cocconema Cistula, Ehr. F. V. nearly linear, obtuse ; V. much
bent, distinctly inflated on the concave margin, obtuse ; striæ moniliform,
24 in -001". Length -0008" to -0034". v.v.
Ehr. Inf. xix. 7 ? Kütz. Bacill. vi. 1. Hass. Alg. ci. 3. In Conjugation, Thw.
Ann. vol. xx. pi. xxii. E. Cymbella renformis, Ag. Consp. p. 10 ad
specim. authen. quæ misit cl. Dr. Greville.
Fresh water : frequent Near Lewes, Mar. 1850. In Conj. Plumpton,
Sussex, Apr. 8o2, &c., W. Sm. AberdeensHre, Dr. Dickie. Lmgh Mourne
Deposit. Dolgelly Earth, &c. &c.
Plates XXHL 221. XXIV. 221. Frustules with endochrome. Frontispiece,
fig. CCXXI.
4. Cocconema parvum, n. sp. F. nearly direct; F. V. oblong;
V. scarcely inflated on concave margin; striæ moniliform, 21 in
■001". Length -0009" to -0016". v.v.
Fresh water. Surface of Chalk cliff, Beachy Head, Aug. 1850. In Coni
Apr. 1851, W. Sm.
Plates XXIII. 222. XXIV. 222.
G e n u s 2 5 . DORYPHORA, Kütz.
Frustules stipitate, lanceolate, or elliptical ; valve with a median line ;
nodules obsolete.
Distinguished from the last by the median line dividing the valve
into two symmetrical parts, and by the absence of distinct nodules.
The second species, upon which the genus has been founded by Professor
Kiitzing, has been seen by him in its living state, attached by
a short stipes to larger Algæ. I have only found it in my gatherings
after the frustules have become detached from their filaments ; but
the first species has occurred to me abundantly in a living state, and
I have been able to refer it with confidence to the present genus, to
which it is more closely allied than to Cocconema, with which genus
writers have hitherto classed it.
1. Doryphora Boeckii, W. Sm. F. V. lanceolate, obtuse; V. lanceolate,
acute ; striæ moniliform, 24 in -OOl". Length -0026" to
•0053". v.v.
Cocconema Boeckii, Ehr. Inf. xix. 5. Kütz. Bacill. vi. 5. Quek. II. C. xii. 7.
Marine. Poole Bay, Mar. 1849, W. Sm.
Plate XXIY. 223.
2. Doryphora Amphiceros, Kütz. V. orbicular, elliptical, or elliptical
lanceolate ; striæ moniliform, 18 i n -001". L e n g th -0012" to
•0033". v.s.
Kütz. Bacill. v. 10. xxi. 2. Prit. Anim. xvii. 21. B,haphoneis, Ehr. in Bail.
Sound. 6I-65.
Marine. Poole Bay, Sept. 1851, &c., W.Sm. River Thames, Mr. iS^orf-
boU. Near Ipswich, Mr. Hodgson.
Plate XXIAA 224. a' and a", outlines of other forms.
G e n u s 26. GOMPHONEMA, Ag.
Frustules stipitate, cuneate ; valves variable in outline, striated, with
a median line and nodules at centre and extremities.
The cuneate form of its frustules, arising from the unequal development
of the connecting-membrane, distinguishes Gomphonema from