A Revision of the Genus Myxine. 395 



XLIV. — ^l Revision of the My.vinoids of the Genus Myxine. 

 By C. Tate Ueoan, M.A. 



(Published by permission of the Trustees of the British Museum.) 



In 1912 ('Annals,' (8) ix. p. 534) I publislied a synopsis of 

 tlie genus Heptatretus, comprising tlie Myxinoids with 6 to 

 14 branchial apertures on each side and with the external 

 branchial ducts subequal in length. A related genus, Para- 

 myxine^ Dean, with 6 brancliial apertures on each side, 

 approaclies Myxine in that the apertures are approximated 

 and the anterior external ducts are longer than the posterior 

 ones; there is a single species from the Sagami Sea, Japan, 

 viz. P. atami, Dean (Journ. Coll. Tokyo, xix. 1906, Art. 2, 

 p. 11, fig. D, pp. 14 & 22, pi. i. figs. 3-5). Myxine is the 

 only other genus of the family. 



Myxine. 



Myxine, Linn. Syst. Nat. ed. 10, i. p, 650 (1758). 

 Gastrobrajichus, IJlocb, Ausl. Fiscb. xii. p. 66 (1795). 



Myxinoids with 5 to 7 branchial sacs, and with a single 

 external branchial aperture on each side. 



Atlantic coasts of Europe and N. America ; Pacific coast 

 of C'olombia ; Chile and Patagonia ; South Africa; Japan. 



The species are all extremely similar, and the characters of 

 most importance in distinguishing them appear to be the 

 number of the teeth and of the pores on each side of the 

 body ; the teeth increase in number as the fish grows, so tliat 

 the size of the specimen has to be taken into account. The 

 length of the head, measured to the branchial aperture, and 

 the number of bi'anchial pouches are the only other characters 

 that seem of any value. 



Of three new species described, two, M. atlantica and 

 M. capensis, are each based on a single unsatisfactory 

 specimen. But, taking into consideration the locality and 

 tiiat in one or more characters they appear to be outside the 

 limits of variation of the other known species, it seems 

 better to describe them than to postpone this revision indefi- 

 nitely in the hope of more material. 



1. Myxine garmani. 



Myxine garmani, Jord. & Snvd. Proc. U.S. Nat. Mus. xxiii 1901 

 p. 731. 



6 branchial pouches. 11 or 12 teeth in the first series the 



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