176 
ZOOLOGICAL LITERATURE. 
Ninth group : Crenuchina. 
43. Crenuchus (Gthr.) witli 1 species. 
Tenth group : Seiuiasalmonina. 
44. Mi/lesinus (C. & Y.) with 1 species. 
45. Serrasalmo (Lac^p.) with 16 species, two of which are new : S. scaptc- 
laris (p. 368) and S. gymnogenys (p. 371). 
46. Myletes (Gthr.) with 27 species, two of which are new: M. parma 
(p. 374) and M. ellipticus (p. 376). 
47. Catoprion (M. & Tr.) with 1 species. 
Cyprinodontes. 
/ Pwcilia. Prof. Peters does not agree with Dr. Bleeker in considering that the 
West- African PiBcilice described by A. Dum^ril are generically distinct from 
the American species j he describes two new species from Liberia — Pwcilia 
bensonii (p. 395) and Paecilia sexfasciata (p. 396), and reunites P. surina- 
mensis (0. & V.) with P. vivipara (Bl., Schn.), adding a few remarks on the 
typical specimen of the latter. Monatsber. Acad. Wiss. Berl. 1864, p. 395. 
Mormyrid^. 
Dr. Marcusen lias chosen this family for the subject of a 
separate monograph, which is published in the seventh volume 
of the M^m. Acad. Sc. St. Petersh. 1864. It is divided into a 
larger, anatomical part, and a smaller, zoological one. The 
former is illustrated by five plates. 
In the anatomical part very detailed descriptions of the 
various organs are given, and particular attention is paid to 
their modifications in the different species. With regard to the 
peculiar cerebral appendage of the fishes of this family. Dr. 
Marcusen is of opinion that it is a special organ, which does 
not correspond homologically to any part of the brain of other 
fishes ; however, its intimate connexion with the brain and its 
uninterrupted continuity with the cerebellum tend to show that 
it is really a part of the brain, and not merely an organ annexed 
to it. If we look for an homologous part in the brain of 
other Teleosteij it is the cerebellum alone which can be con- 
sidered such. 
The zoological part does not contain the latest additions to 
our knowledge of this family,' hut gives original descriptions of 
the more common species of the Lower Nile ; and the other 
species described by Valenciennes and Peters are also charac- 
terized. Dr. Marcusen adopts four genera: 1. Mormyrus {M. 
oxyrhynchus, M. anguilloideSj &c.) ; 2. Mormyrops (M. cypri- 
noides) ; 3. Phagrus {Ph. dorsalis) ; 4. Petrocephalus (M. bane, 
&c.). The Pecorder^s own researches on this family have led 
him to a somewhat difierent division of the species, as will be 
shown in our next Report. 
, Dr. Gunther has described a new species of Mormyrus^ M. tamandua, from 
^ West Africa, Proc. Zool. Soc. 1864, p, 22 j it is figured on plate 2, togetlier 
with another species lately described, M. petersii (Gthr.). 
