342 Transactions of the Society. 



had they taken the trouble to glance over the species previously 

 described. 



Several have been described without accompanying figures. 

 These must be rejected, as it is impossible to construct from the 

 descriptions any approximate image of the animals described. 



Before describing a '' new species," the student should first 

 pass in review all the known species of the same group. Having 

 ascertained that his animal is quite unlike any of them, he may 

 proceed to describe and figure it. The figure should show the general 

 form accurately. All the principal dimensions should be noted. 

 In this family the specific characters appear most clearly in fully 

 contracted specimens. The anterior margins have very definite 

 and constant outlines, which only appear in full contraction. 



The characters by which species are distinguished are few : 

 the relative proportions of the dorsal and ventral plates, of which 

 sometimes one, sometimes the other, may be broader; the depth 

 of the lateral sulcus ; the outlines of the anterior margins, dorsal 

 and ventral, in contraction ; the depth of the lorica ; the promin- 

 ence of the foot ; the form of the toes, in both dorsal and lateral 

 views if possible, and whether shouldered ; lastly, the faceting or 

 wrinkling of the dorsal plate, and any other peculiarity noticed. 



The tigure should always show the dorsal view, which is most 

 important. If the ventral plate has any distinctive peculiarities, 

 it should be figured also. It is desirable that a lateral view should 

 also be given, when possible. 



The dorsal and ventral anterior margins sometimes exactly 

 coincide. When they do not, the ventral is always more deeply 

 cut, at any rate in the middle. The part of the ventral margin 

 covered by the dorsal can be indicated by a dotted line. 



In the three plates accompanying this section of the paper, 

 considerations of space have prevented me from observing all my 

 own suggestions. It has not been possible to give the lateral 

 views of the new species. But all essential specific characters are 

 given in every case. 



In order to avoid needless multiplication of figures, both dorsal 

 and ventral plates are usually shown in one figure, the ventral 

 plate being indicated by a dotted line when it is smaller than the 

 dorsal. The sulcus is also indicated by a dotted line. To avoid 

 confusion, the ventral plate, wlien hidden, is indicated by a series 

 of long dashes, the sulcus by very short dashes or by dots. 



In order further to bring out the important distinction between 

 the dorsal and ventral plates, the dorsal is drawn with a thicker 

 line. While to this extent rendered diagrammatic, the figures are 

 otherwise as faithful pictures as I could make. 



I find previous records of seventeen species of Cathy pnidge for 

 South America, including those in my Bolivian list (^^).* Several 



* The figures in brackets refer to the Bibliography at the end of this paper. 



