4 T. THORELL, 
As fundamental principle we of course go out from the so called 
Lex Prioritatis, which ordains that each genus preserve the generic name, and 
each species the specific name, by which it was first made known; the name of 
the person, who frs described or figured such genus or species under 
the aforesaid name, being added as authority”. The reasonableness of this 
law is so clear and evident, that I should not have thought it necessary to 
mention it, were it not that there are persons (even among arachnologists), 
who seem to live in total ignorance of its existence and of every one’s du- 
ty to conform to it.) Simple as this rule is, some difficulties present them- 
selves in its application, which may give rise to differences of opinion. 
One might e. g. ask in what manner a name ought to be given in order 
to have the right of being preserved. We conceive that the name ought to 
be followed by a definition or characterization of the object named, i. e. either 
(which is preferable) a description (diagnosis), or a figure, or at least a refe- 
rence to some previously existing description or figure; moreover that such 
name and accompanying characterization ought to be printed and published; 
that accordingly no other denominations than those, which have been giv- 
en in the above named manner, can, in fixing the scientific nomencla- 
ture of animals (and plants), be taken into consideration. Hence it follows 
.that no one needs pay any attention either to names published in print 
unaccompanied by descriptions,?) nor to denominations given to natural 
1) That the scientific names of animals and plants must be Latin (i. e. have a 
Latin form) would seem to be selfevident. Any person then, who describes a new 
species by e. g. a French name only, cannot expect that a such denomination should 
be respected on the ground of priority. If such names, for example, as Athelgue 
cladophore, Prostèthe cannelé (Vid. Hesse, Mém. sur deux nouv. genres de l'ordre des 
Crust. sédentaires ete. in Ann. des Sciences Nat., 4 Ser., Zool, Tom. 18) are to be 
generally used, they must first be provided with a Latin form, and the right of prio- 
rity (and authority) must be assigned to the work, where these animals are first en- 
tered with their Latin denominations. For this reason we consider that e. g. the 
genus called by LATREILLE in his Cours d'Entomologie, 1831, Gastéracanthe and 
which SUNDEVALL in his Conspect. Arachn. 1833 calls Gasteracantha (Gastracanthus 
Wesrw. 1835), must be properly designated as Gasteracantha (SUND.) 1833. 
2) If, when a genus has been once set up and characterized, there should be 
given, as a type of it, some species, named indeed, but not farther described, but 
concerning which no uncertainty is possible, I think that also such specific name ought 
to be retained Not only the genus but the species is in this case sufficiently di- 
stinguished by the characteristics of the genus. An example of this is afforded by 
Filistata testacea LATR. 1810 (= F. bicolor WALCK. 1820—25). 
Neither does it appear reasonable, when a species has been described under a 
new generic name, to reject such generic name simply because the characteristics, 
