466 
Miscellaneous. 
This Peruvian fish however is interesting from its showing that there 
exist fishes there which live principally upon infusorial mud. Whe- 
ther this occurs upon an extensive scale and also in the case of the 
salt-water fish of that country must be left to further inquiry. 
In the small sample of the contents of the stomach forwarded, the 
following species have been determined : — 
PoLYGASTRICA 27. 
Amphora gracilis. 
Cocconeis fasciata. 
Placentula. 
Cocconema Leptoceros. 
Lunula. 
Coscinodiscus radiolatus } 
Discoplea ? (Gallionella ?). 
Eunotia gibba. 
Fragilaria acuta. 
rhabdosoma. 
Glceonema paradoxum ? 
Gomphonema gracile. 
Augur. 
Himantidium Arcus, 
Navicula lineolata. 
Scalprum. 
Pinnularia affinis. 
borealis. 
peregrina. 
viridis. 
Podosphenia Pupula. 
Synedra acuta. 
constricta ? 
Entomon. 
Sphenosira Catena. 
Stauroneis linearis. 
Stauroptera Monogramma. 
Phytolitharia 4. 
Lithostylidium Clepsammidium. Lithostylidium rude. 
Rajula. Trabecula. 
It is evident from this list that the river water in which the fish 
was taken contains an admixture of sea animalcules {Coscinodiscus), 
and consequently is situated either w'ithin the tidal reach of the 
ocean, or, as only fragments of the marine form were noticed, flows 
over tertiary biolithic deposits. Cocconeis fasciata is likewise a 
known form from the coast of Peru. 
Synedra Entomon, known hitherto only from Chili, is remarkable 
from its occurrence in the dust of the trade-winds. Synedra ? con- 
stricta is a smooth form characteristic from its two extremities being 
drawn out into two long-pointed needles. Stauroneis linearis and 
Sphenosira Catena are known American forms from Chili and Mexico. 
Stauroptera Monogramma is a ribbed form resembling the smooth 
Stauroneis Monogramma from Surinam, which is again similar to but 
not identical with Achnanthes ventricosa. — Report of the Berlin Aca- 
demy, Jan. 1848. 
Discovery of the Maxillary Organs of the Iguanodon. 
Dr. Mantell’s researches have at length been rewarded by the 
discovery of portions of both the upper and lower jaw of the Igua- 
nodon, nearly thirty years after his first announcement of the form 
and structure of the teeth of that colossal herbivorous reptile. 
The form of the maxillary organs of the Iguanodon is most ex- 
traordinary, and entirely differs from anything previously known in 
the class of reptiles, I'he configuration of the lower jaw approaches 
