NO. 8 OPINIONS 124 TO 133 37 



OPINION 131 



The Type Species of Trumikosoina Morti^nsen, 1903 



Summary. — The type species of Tromikosoiua is T. kochlcri. 



Presentation of case. — Dr. Murtensen, of Copenhagen, has pre- 

 sented the following case for Opinion : 



Pomel, in his paper " Classification methodique et Genera des Echinides vivants 

 et fossiles ", 1883, p. 108, established a genus Echinosovia, citing the species 

 Phormosoma uramis A. Agassiz and Phormosoma tennis A. Agassiz as belonging 

 to that genus without designating any of them as the genotype. 



In my work " Echinoidea I. The Danish Ingolf Expedition ", vol. 4, no. i, p. 62, 

 1903, I adopted the said genus of Pomel, referring to it the same two species as 

 did Pomel, but no genotype was designated. In this same work I established the 

 genus Tromikosoiua, with the single species Troinikosoiiia kochlcri n. sp., which 

 is accordingly the genotype of that genus. 



A. Agassiz and H. L. Clark, in their work " Hawaiian and other Pacific 

 Echini. The Echinothuridae " (Mem. Mus. Comp. Zc)ol., vol. 34, no. 3, p. 160, 

 1909) designate Phormosoma fciiiic A. Agassiz as the genotype of Echinosoma, 

 which is made to include also my genus Troiiiikosoma — which I agree to be 

 correct. 



The name Echinosoma, however, was preoccupied, no less than three times: by 

 Audinet-Serville, 1839, for an earwig: by WoUaston, 1854, for a beetle; and by 

 Semper, 1868, for a Holothurian. Accordingl3% it cannot be used for the echinoids, 

 and the name Tromikosonia must take its place. 



Which species is now to be the genotype of Tromikosoiua, Phormosoma tenuc 

 A. Agassiz or Tromikosoiua kochlcri Mrtsn.? 



I would think the latter ought to remain the genotype of Tromikosoiua also 

 in its extended sense. But the matter does not seem to me quite clear, so it 

 would seem better to have the Commission give its Opinion about the case, and 

 to give it a more general form. I may then put the question thus : When an 

 older genus proves to be a synonym of a later genus, which species is then to be 

 regarded as the genotype, that of the older or that of the later genus ? 



Discussion. — This case was submitted to the Commission in 

 Circular Letter No. 252 for informal expression of Opinion and in- 

 formal vote. As a result the following ten Commissioners registered 

 their view that the species kochlcri. is the correct type: Apstcin, 

 Bather, Chapman, Fantham, K. Jordan, Peters, Richter, Silvestri, 

 Stiles and Stone. The following two Commissioners view the species 

 tenne as the type : Ishikawa and Pellegrin. 



The informal votes were accompanied by the following views : 



Chapman remarks : " Tromikosoiua kochlcri is monotypic and founded by 

 Mortensen in 1903. Therefore that species has priority [as genotypc-C. W. .S.] 

 over tcnue (Phormosoma) selected by Agassiz and Clark in 1909." 



