16 CLEVE, DIATOMS FROM THE WEST INDIAN ARCHIPELAGO. 
Journ. II pag. 16 PI. 1 fig. 10. Amphitetras arisata 
JAN. & RAB:  Hond; PI o1-fig: 2) Mirgm Ids abundant 
145. T. punetatum Brw. (Mier.! Journ. IV pag. 2075 Pl 17 
fig. 18. PrirckH. VI fig. 20. Tricer. sculptum SHADE. 
Trans Micr. Soc. pag. 15 PI. 1 fig. 4. Trie. reticulum 
[EFaB.2)/ Brw. M. Ji Iopag: 251 Pl4rfig. LT) Mitgim Idsj 
St. Bartholomew, abundant. 
The frontview has exactly the same appearance as Tr. 
reticulum BiTW. the sideview resembles T. sculptum of Shadb. 
T. punctatum is said to occur in arctic regions. I have never 
found it in the many arctic gatherings, which I have examined. 
The puncta are on the West Indian form often arranged so 
that they form 3 circlets in the middle of the valve, just as 
on the figure of T. sculptum SHADB. This species in widely 
distributed. I have seen it, but rarely, from the western 
coasts of Sweden, from the Mediterranean (Balearic Islets), 
Honolulu, Java etc. 
146. T. obtusum EumB. (M. G. Pl. 18 fig. 48—49) St. Bartholo- 
mew, rare. 
This species occurs very abundantly in the well known 
Campeche Bay gathering. I have found it very frequently in 
shellsand from the Gallopagos Ids. The surface of the valve 
is plane or a little elevated in the middle and on the mar- 
gins, but the angles never project in horns. The outline is 
very variable; the sides are sometimes straight, sometimes 
more or less convex, resembling T. disciforme Grev. (T. M. 
S. II PI. 9 fig. 11) but probably not the same. I have seen 
both in the Gallopagos and Campeche Bay gatherings specimens 
with a perfectly circular outline, resembling Coscinodiscus mos- 
sianus GrREv. (Trans. micr. Soc. XIII Pl. 4 fig. 22). It seems 
therefore that Triceratium is not more strongly defined from 
Coscinodiscus, than from Biddulphia. 
147. T. Campechianum GRUN. in litt. Virgin Ids., very rare. 
The only specimen of this beautiful species, which I found 
in the gatherings from Virgin Ids., agrees perfectly with spe- 
cimens from Campeche Bay, kindly sent me by Dr. GRÖNDLER. 
The fig. 28 22 is copied from a photograph of a specimen 
from Campeche Bay. 
148. T. Antillarum Cr. N.Sp. Small, 4-angular to 5-gonal, with 
produced angles. Sculpture: small, pearly granules, 7—38 
in 0,01 m.m., arranged in straight, radiating lines. The 
