!l
W. Sm. 2nd Ser. vol. rii. pi. i. 3. C. Argus, Bail. Obs. pi. ii. 24. 2.5. ad
specimina quæ communicavit Prof. Williamson, Jan. 1852.
Marine or brackish water. Poole Bay, Nov. 1848. Lewes, 1850, W. Sm.
Coast of Norfolk, Mr. Brightwell. (Hudson River.)
Plate VII. 55.
6. Campylodiscus parvulus, W. Sm. Valves circular ; canaliculi
about 12, minute, in length about two-thirds of radius. Diam. -0011 "
to -0019". v.v.
W. Sm. Ann. 2nd Ser. vol. vii. pi. i. 4. Prit. Anim. xxiv. 22, 23.
Poole Bay, 1848, TF. Sm.
Plate VI. 56.
7. Campylodiscus Ralfsii, n. sp. V. nearly circular, canaliculi
reaching to the median line. Diam. -0016" to -0019". v.s.
Marine. Ilfracombe, Mr. Ralfs.
Supp. Plate XXX. 257.
Genus 13. SURIRELLA,
Frustules free, ovate or elliptical; valves with a longitudinal central
line, and margins produced into alæ ; canaliculi distinct, usually
parallel.
The only genus with which the present stands in near alliance is
Tryblionella, from which it is well distinguished by the prominency of
its alæ, the distinctness of its canaliculi, and the usual cuneate form
of its frustules : with no other is it at all likely to be confounded. The
surface of the valve in Surirella, as in the other Diatomaceæ, is marked
with transverse lines ; these are usually very faint in the present genus,
but in a few cases they are somewhat conspicuous and have been
noted in the specific descriptions.
1 . Surirella biseriata, De 5re5. F. V. linear, oblong ; V. elliptical-
lanceolate; alæ conspicuous; canaliculi large, 4 to 6 in -OOl",
usually reaching to central line. Length -0025" to -0083". v.v.
De Bréb. Alg. Falaise, 1835, p. 53. pi. vii. ad spec, authen. quæ communicavit
cl. auctor. Hass. Alg. cii. 1. W. Sm. Ann. 2nd Ser. vol. vii.
pi. ii. 1. Prit. Anim. xviii. 20-26. Jen. Flo. Tun. p. 204. Nav. bi-
frons, Ehr. Inf. xiv. 2. Surirella hifrons, Kiitz. Bacill. vii. 10.
Fresh water. Boggy pools frequent, elsewhere occasionally. Wareham,
Dec. 1849 ; Lewes, Sept. 1851, TV. Sm. Ashdown Forest, Sussex, Mr. Jenner.
Lough Mourne and Lough Island-Reavey Deposits, and Premnay Peat.
Plate VIII. 57. Frustule with endochrome. Frontispiece, fig. LVII.
V. linear, occasionally 2. Surirella linearis, n. sp. constricted,
obtuse or acuminate, v.v.
With the last, and probably varieties of it and S. splendida. Curwen Hill
Lot near Lancaster, Mr. Geo. Smith, 1851. Snow Mud, Ben M' Dhui,
Dr. Dickie. Cantyre Peat, &c.
Plate VIII. 58.
3. Surirella constricta, W. Sm. F. V. linear, oblong ; V. elliptical,
acute, usually with a central constriction ; alæ conspicuous ; canaliculi
delicate, 10 to 12 in -OOl", reaching to central line, which is
often inflated. Length '0028" to "0055". v.v.
W. Sm. Ann. 2nd Ser. vol. vii. p. 9.
Brackish water. Near Lewes, Dec. 1850. Poole Bay, Sept. 1851. Lancing,
Sussex, Nov. 1852, TF. Sm.
Plate VIII. 59.
4. Surirella turgida, n. sp. V. much inflated, irregular in outline,
occasionally somewhat constricted towards the ohtuse extremities ;
canaliculi few, conspicuous, 4 in 'OOl". Length '0033" to 0052".
v.s.
Fresh water. Lough Neagh, Dr. Dickie, 1850.
Plate IX. 60.
5. Surirella lata, n. sp. V. elliptical, with rounded ends and
frequently w ith a central constriction ; canaliculi conspicuous, 3 or
4 in -001" ; margin striated ; striæ 36 in -OOl". Length -0041" to
•0062". v.s.
Marine. Coast of Skye, Prof.
. Ilfracombe, Mr. Ralfs.
Plate IX. 61.