8 THÉEL. NORTHERN AND ARCTIC INVERTEBRATES. II. PRIAPULIUS, ECHIURIDS ETC. 



1903. Augener. Archiv f. Naturgeschichte, LXIX. I. 3, Berlin. 



1903. Norman. Ann. and Mag. of Nat. History, VII. 12, London. 



1904. Hértjbel. Bull. la Société zoologique de France. XXIX, Paris. 



Critique of the Priapulida and Echiurida, known to inhabit the Northern and Arctic 

 Seas, and of the questionable Genera Saccosoma and Epithetosoma. 



When I am going to submit the Priapulids and Echiurids to a discussion, I must 

 not be suspected to do so from the assumption of a closer relationship between them. 

 Their relation is certainly very distant. 



I may be allowed in the first place to discuss the Priapulida. This group or 

 rather suborder appears to be fairly well defined and comprehends only the two well 

 known genera: Priapulus Lam. and Halicryptus v. Sieb. 



In the first place with regard to the genus name »Priapulus», given by Lamarck 

 in 1816, I entertain great doubts whether it is right to maintain this name, though 

 it has been accepted for a long time in the literature. As early as 1758 and 1759 

 Linné described the genus in such a manner that there can be no doubt what he 

 meant. 1 But he called the animal with the genus name »Priapus», a name which 

 evidently must be retained, though I myself feel it distasteful to change an okl fa- 

 miliar name for another, older, it is true, but neglected. 



Furthermore, with regard to the genus names Priapulopsis and Priapuloides of 

 Koren and Danielssen, they ought to be placed among the synonymes under 

 Priapulus or Priapus. In 1868 Danielssen himself referred the species bicau- 

 datus» to the old genus Priapulus of Lamarck [Priapus of Linné] and, to my thin- 

 king, he was right in doing so, because the characters distinguishing this form from 

 the caudatus , known long before, can by no means be of generic value. Never- 

 theless, as early as 1875 the Norwegian investigators were ready to exchange this 

 genus name for Priapulopsis, to refuse their own species name bicaudatus» and to 

 substitute »typica» for it. Låter on, in 1877, they again shifted the genus name 

 from Priapulopsis to Priapuloides with maintenance of the species name »typica». 



Thus, according to my views, there are only known two genera of the suborder 

 Priapulida, viz. Priapulus and Halicryptus, the former with the two species caudatus 

 and bicaudatus, the latter with the single representative »spinulosus». 



If we now pass on to the Echiurida we will find that the two Norwegian in- 

 vestigators, Danielssen and Koren (1877 — 1881) have though t it disposed into three 



1 Linné writes in his Amoenitates Academicaé, IV. p. 255: 

 Corpus pallidum, penem quodammodo referens. 



Truiints löngitudine & crassitie pollicis. cinctus striis annularibus XL. 

 Basis ipsa costat rugis CXI terminalibus, papillis subulatis, mollibus. 



Hinns (ivalis exarata striis XXIV, muricatis; os glandis cinctum niga seu sulco profundo, in cujus eenjtrp 

 Concavitas, cincta Unguibus XII incurvis, prominet rostro cylindrico, radiis composito. 



Every one will understand, that Linné by this diagnosis characterized the genus Priajniliis of Lamarck. 



