326 Notes on Map Projections. 
IV. ANOMOBRANCHIATA. 
XXIV. The Mysidea, to which the Penzidea are related, are, 
to a considerable extent, cold-water species, although many are 
found also in the tropics. There are among them twenty torrid 
species and seventeen extra-torrid species. 
In the Squilloidea we have an example of an inferior grade in 
a large lax body, with a small head and long abdomen; and they 
sively to the Temperate zone. Of the Erichthide, twenty-one 
out of twenty-two species are reported from the Torrid zone. 
The Amphionidea, a related group, include seventeen Torrid 
zone species and two of the T’emperate zone. 
(Zo be continued.) 

Art. XXXV.—Notes on Map Projections ;* by Lieut. E. B. 
Honr, Corps of Engineers, U. S. A. 
MAP PROJECTIONS CLASSIFIED AND DEFINED. 
Tar department of descriptive geometry, or analysis, which 
treats of map and chart projections, has to deal solely with the 
terrestrial spheroid, and especially with the representation of the 
parallels and meridians subdividing its surface. As all localities, 
both on land and sea, are most readily and generally determin 
by latitude and longitude observations, so it is the most available 
and universal method, in constructing maps, to refer all positions 
to meridians and parallels as codrdinate lines. 
If we conceive the earth’s surface reticulated by a complete 
framework of parallels and meridians, it is then the specific an 
uniform object of all modes of projection to represent these lines 
on a plane surface, in the most advantageous manner. But, 3 
the spheroid is incapable of direct development on a plane, it only 
remains to present, in projection, the best approximation to sim= 
itude in form, relation, and proportional area in the parts of the 
earth’s surface to be represented. 
Ptolemy, Lambert, Euler, Lagrange, De l’Isle, Monge; csi 
Croix, Puissant, Henry, Gauss, and others, have treated 0 oe 
jections in more or less detail, and some of them by methods © 
* Extracted with modificati eport for 1853, in ae 
is also included the Pte for polyeutie projections, wich fall tables and ® era 4 
tion. The Tables suffice for the entire United States on either large or small 
