166 
Transactions of the Royal Microscopical Society. 
Asterionella. 
Asterionella Bleakeleyi Wm. Sm. var. notata Grun. Valvarum 
parte inferiore inflata, costa transversa arcuata notata. Strife 
transversse tenerrimse 36-38 in '01 mm. Tab. CXCIII., Fig. 2. 
I am doubtful whether this form should be referred to 
A. Bleakeleyi, as I can find no trace of the very conspicuous 
transverse costa in the various delineations of this diatom (‘ Q. M. J.,’ 
vol. viii. pi. 7, fig. 10. Lewis’ Diatoms of the United States Sea- 
board, pi. 2, fig. 9). 
Synedra. 
Synedra laevigata (Grun.) n. sp. ( S . gracilis var. ? tenuissime 
striata, Grun. in Hedwigia, s.p.). S. major a latere primario linearis, 
ad polos paululum attenuata, valvis anguste lineari lanceolatis 
acutiusculis, striis transversis tenuissimis(plus quarn 38 in • 01 mm.). 
Longit. - 08- ‘24 mm. Tab. CXCIII., Fig. 3. 
I have seen this diatom from various localities (Honduras, 
Mauritius, Samoa Islands,) but I have never been able to detect 
more than traces of a striation even by monochromatic illumina- 
tion. 
Allied to this species is another, and often accompanying it, but 
which differs in the valves being more linear and the apices more 
obtuse ; the striation is also coarser, and exactly resembles that of 
Amphi pleura pellucida. I have named it S. laevigata var. ? 
obtusiuscida. Length • 08- • 30 mm. Striae 38 in ■ 01 mm. 
PI. CXCIII., Fig. 4. 
Mauritius (by Ida Pfeiffer), Samoa Islands (Dr. Graeffe). A 
third species or variety nearly allied is 
Synedra laevigata var. ? hyalina, which I found on llalop- 
legma Preissii, from South Australia. It is much smaller, with 
lanceolate valves and slightly produced obtuse apices. Length 
•04-‘052 mm. Striae about 38 in ‘01. PI. CXCIII., Fig. 5 ,a, b. 
The median line of all these Synedreae is narrow. A fourth 
allied Synedra with coarser striation is 
Synedra provincialis (Grun.) n. sp. S. minor a latere primario 
sublinearis, valvis lineari lanceolatis, polis paululum tumidulis, 
suhtruncatis, linea media angusta, striis transversis tenuibus 30 in 
•01 mm., nodulis terminalibus conspicuis. Longit. 065- 'll mm. 
Tab. CXCIII., Fig. 6. 
Habitat in mari Meditteraneo ad oras Gallia} prope Cette (leg. 
L. Lindig). 
S. provincialis var. tortuosa. Valvis plus minus undulato 
tortuosis. Tab. CXCIII., Fig. 7. Upolu, Samoa Islands, leg. Dr. 
Graeffe. The peculiar undulations of this variety occur also in 
other species of Synedra (S. ulna, S. oxyrhynchus, &c.). 
