362 Bulletin of Zoological Nomenclature 

PROPOSED USE OF THE PLENARY POWERS TO VALIDATE THE 
SPECIFIC NAME " CONVEXA" DE HAAN, [1835], AS PUBLISHED 
IN THE COMBINATION " OCYPODE (CHASMAGNATHUS) CON- 
VEXA", THE NAME OF THE TYPE SPECIES OF THE GENUS 
"CHASMAGNATHUS" DE HAAN, [1835] (CLASS CRUSTACEA, 
ORDER DECAPODA), PLACED ON THE "OFFICIAL UST OF 
GENERIC NAMES IN ZOOLOGY" BY THE RULING GIVEN IN 
" OPINION " 85 

By FRANCIS HEMMING, C.M.G., C.B.E. 
(Secretary to the International Commission on Zoological Nomenclature) 

(Commission Reference : Z.N.(S.) 984) 

The purpose of the present application is to ask the International Commission 
on Zoological Nomenclature to use its Plenary Powers to validate the specific 
name currently used for the type species of the genus Ghasmagnathus de Haan, 
[1835] (Class Crustacea, Order Decapoda), which was placed on the Official 
List of Generic Names in Zoology by the Ruling given in Opinion 85 (1925, 
Smithson. misc. Goll. 74(No. 3) : 13-18). 

2. The existence of the present problem came to light in the early part of 
1955 when proposals were being formulated for submission to the International 
Commission for the addition to the Official List of Specific Names in Zoology 
of the specific names of the type species of the genera of Decapoda, the names 
of which had been placed on the Official List of Generic Names in Zoology 
in the pre-Lisbon (1935) period. The facts of this case are set out in the follow- 
ing paragraphs. 

3. The name Ghasmagnathus was introduced by de Haan in the Crustacea 
Section of von Siebold's Fauna japonica for use as the name of a subgenus 
of Ocypode Fabricius, 1798. This name occurs twice in the Crustacea Section, 
first on page 5 and later on page 27. These pages were pubhshed in Parts 1 and 2 
respectively, the first appearing in 1833, the second in 1835. On page 5 the 
name Ghasmagnathus was given only in a key without any cited nominal 
species ; on page 27 the subgenus was more fully diagnosed and one species, 
the new species Ocypode (Ghasmagnathus) convexa, was cited as belonging to it. 
This species is therefore the type species of Ghasmagnathus de Haan by 
monotypy. 

Bull. zool. Nomend. Vol. 11, Part 12. November 1956. 

Bulletin of Zoological Nomenclature 363 

4. Reference to Sherborn's Index Animalium (Pars secund. (7) : 1505) 
disclosed the existence of the name Ocypode convexus Qouy & Gaimard, 1826 
{Voy. " Uranie " (Zool.) : 525). Since for the purpose of determining whether 
any two specific names are homonyms of one another the only relevant con- 
sideration is whether the generic name and the specific name employed is the 
same for each case the name convexa de Haan, [1835], as pubhshed in the com- 
bination Ocypode (Chaamagnathtis) convexa, is a junior primary homonym of 
Ocypode convexus Quoy & Gaimard, 1825, and is therefore invalid. 

5. Clearly the first matter to be investigated was the present status of the 
name Ocypode convexus Quoy & Gaimard, a name which had apparently 
escaped the sharp eye of the late Miss Mary Rathbun when she drew up the 
application upon which the Crustacea section of the Ruling given in Opinion 85 
was based. On this subject I first applied to Dr. Isobel Gordon {British 
Museum (Natural History), London) who, after checking the literature, informed 
me that the foregoing name did not appear to have been used by any authors 
since Quoy & Gaimard. I thereupon extended my inquiries by seeking the 
advice of the following speciaUsts : 364 Bulletin of Zoological Nomenclature 

validate the action taken at the time when the name Chasmagnathus de Haan 
was placed on the Official List of Generic Names in Zoology by :