
No. 458.] NOTES AND LITERATURE. | 95 
374 in all, with excellent plates, the work of Mrs. Chloe Lesley 
Starks, representing most of the new forms. The descriptions are 
prepared with that minute attention to accuracy characteristic of all 
of Dr. Gilbert’s work. Of the many new species, the majority were 
included in the appendix to Jordan and Evermann’s fishes of North 
America. Those not so included are the following: 
Galeichthys eigenmanni, Tachysurus evermanni, Fistularia corneta, 
Oligoplites refulgens, Peprilus snyderi, Sagenichthys (properly Macro- 
dom) mordax, Pomacentrus gilli, Halicheres macgregori, Balistes 
verres, Xesurus hopkinsi, Guentheridia, a new genus of Tetra- 
odontide (formosa), Prionotus ruscarius, Microgobius miraflorensis, 
Evermannia panamensis, Batrachoidea boulengeri, Porichthys greenet, 
Hypsoblennius piersoni. Lythrulon opalescens is not distinguishable 
from Z. flaviguttatum, and Menticirrus simus is identical with M. 
nasus. Eleotris equideus cannot be separated from E. pictus, and 
 Microgobius cyclolepis is the same as M. emblematicus. Ancylopsetta 
sabanensis is identical with A. dendritica, and the genus Ramularia 
is not tenable. Solea fischeri and Solea panamensis are synonyms 
of Achirus fonsecensis. 
The following conclusion as to the relations of the fish faunas on 
the two sides of the isthmus of Panama is of special interest. “ The 
ichthyological evidence is overwhelmingly in favor of the existence of 
a former open communication between the two oceans, which must 
have become closed at a period sufficiently remote from the present 
to have permitted the specific differentiation of a very large majority 
of the forms involved. That this differentiation progressed at 
widely varying rates in different instances becomes at once apparent. 
A small minority of the species remains wholly unchanged, so far as 
we have been able to determine that point. A large number have 
become distinguished from their representatives of the opposite coast 
by minute (but not ‘trivial ’) differences, which are wholly constant. 
From such ‘representative forms,’ we pass by imperceptible grada- 
tion to species much more widely separated, whose immediate rela- 
tion in the past we cannot confidently affirm. Of identical species, 
occurring in both oceans, our Panama list contains 43. 
“ The total number of identical species which we recognize in the 
two faunas now separated by the Isthmus is therefore 54, as compared 
with the 71 enumerated by Jordan (1885). It is obvious, however, 
that the striking resemblances between the two faunas are shown as 
well by slightly divergent as by identical species, and the evidence in 
favor of interoceanic connection is not weakened by an increase in 
