A REVIEW OF THE MYSIDACEA 13 



Genus CHALARASPIDUM Willemoes-Suhm 



Chalaraspis (pars) Willemoes-Suhm, 1876b, p. 592. 

 Chalaraspis G. O. Saks, 1885, p. 50. 

 Chalaraspidum Willemoes-Suhm, 1895, p. 521. 

 Eclytaspis Faxon, 1895, p. 219. 



The genus Chalaraspis was founded by Willemoes-Suhm in 1875 

 to include the species unguiculata. In his Challenger Report Sars 

 showed that the genus Chalaraspis, as defined by Willemoes-Suhm, 

 was clearly the same as the genus Eucopia founded by Dana in 1852, 

 so that the genus Chalaraspis became a straight synonym of Eucopia. 

 In his letters from the Challenger expedition, which were collected and 

 published in 1877 but which had appeared separately at intervals from 

 1873-1877, and also in other reports which he made on the Challenger 

 expedition (1876a), Willemoes-Suhm used the generic name Chala- 

 raspis for another species of mysidacean, C. alata, collected at station 

 158 of the Challenger expedition in the Southern Ocean near Kergue- 

 len. Unfortunately the specimen was lost but notes and a drawing 

 of it were found among the papers of Willemoes-Suhm after his death. 

 Sars utilized these in his Challenger Report and published them under 

 the name Chalaraspis alata. Sars recognized that this species was, 

 in fact, related to the genus Lophogaster and not to Eucopia, but, on 

 the grounds that Chalaraspis unguiculata was a synonym of Eucopia 

 australis, he retained the generic name Chalaraspis for C. alata. This 

 is clearly not in accordance with the accepted principles of zoological 

 nomenclature, and Faxon (1895) on these grounds proposed the 

 generic name Eclytaspis, with C. alata as the genotype. There is, 

 however, another name that I think can be used for this species and 

 ought to have priority. In the two volumes of the "Summary of the 

 Scientific Results" of the Challenger expedition, published in 1895, 

 under station 158 on page 521, appears the following passage: "and 

 a specimen of Chalaraspidum, n. gen., characterized by shorter legs 

 and a much longer carapace, which extends over the third abdominal 

 segment and is extremely soft." It was at station 158 that the only 

 specimen of C. alata captured by the Challenger expedition was taken, 

 and the excerpt quoted above clearly refers to this specimen. The 

 quoted passage is taken practically verbatim from one of Willemoes- 

 Suhm's notebooks under date of March 7, 1874. It would appear 

 that Willemoes-Suhm himself recognized that C. alata belonged to a 

 different genus from Chalaraspis unguiculata, and, had he survived, 

 would no doubt have published this fact. The volume of the "Sum- 

 mary" in which the quoted passage appears was received at the British 

 Museum on March 20, 1895. Faxon's paper in which the name 

 Eclytaspis was published has the date April 1895 on the wrapper. 

 Chalaraspidum, therefore, antedates Eclytaspis by one month. It 



