EEPORT OF COMMISSIONER OF FISH AND FISHERIES. [4] 



§ Lampetra Gray. (3pf.) 



5. Armnocoetes cibarius ' Girard. C. Ana. (7) 



6. AmmoccBtes aureus Bean. A. Ana. {7b) 



$ Ammoccetea. , 



7. Anunocoetes aepypterus'* Abbott. Vn. (8) 



5.— PETROMYZON (Artedl) Linnseus. (7) 

 $ Ichthyomyzon Girard. (6) 



8. Petromyzon bdellium' Jordan. Vn. (9) 



9. Petromyzon hirudo Girard. Vn. (96.) 



10. Petromyzon castaneus Girard. Vw. (10) 



§ Petromyzon. (7) 



11. Petromyzon marinus L. N. Eu. Ana. (11) 

 lib Petromyzon marinus dorsatus Wilder. Ve. (12) 



6.— BATHYMYZON* Gill. 



12. Bathymyzon bairdii^ Gill. B. 



Class III.— PISCES. 



Subclass Elasmobkanchii. 



Order D.— 0PISTHARTHRI.« 



Family V.— IS^OTIDAmD^. (15) 



7.— HEPTRANCHIAS Ralinesque. (32). 

 § Notorhynchua Ayres. 



13. Heptrancbias maculatus Ayres. C. (42) 



8.— HEXANCHUS Rafinesque. (31&.) 



14. Hezanchus corinus Jordan «fc Gilbert. C. (42&.) 



' The name Petromyzon plumieus is preoccupied by Shaw, 1805. 



^ The name Petromyzon niger is preoccupied by Lac6pMe, 1798. This is probably 

 the species poorly described by Abbott as Amm. cppyptera. 



3 The name Petromyzon argenteus is preoccupied by Bloch, 1790. I propose the new 

 name P. IdelUum for this species, as I cannot identify it certainly with Ammoccetes 

 concolor Kirtland, A. iorealia Ag., or any other nominal species, based on larval forms. 



■•Bathymyzon Gill, Proc. U. S. Nat. Mus., 1881?, 254; type Petromyzon {Bathymyzon) 

 hairdii Gill. (/3a0u5 — deep; /iv^cio-^to suck.) This genua is said to differ from Petro- 

 tnyzon in having " the suproral and infroral plates or laminae destitute of odontoid 

 tubercles, the armature of the lamprey type being obsolescent." 



5 Petromyzon {Bathymyzon) hairdii Gill., 1. c. 254, Gulf Stream, latitude 40°, at a depth 

 of 547 fathoms. The species has not been described, except that it is " closely related 

 to Petromyzon marinus." 



^The groups called Opistharthri and Proarthri, certainly worthy of ordinal distinc- 

 tion from the other Sharks, are defined by Professor Gill in our Synopsis Fish. N. A., 

 967. 



