868 CONTRIBUTIONS TO NORTH AMERICAN ICHTHYOLOGY IV. 



Page 7. The genus 4 («) Entosphentis sliould probably be admitted, 

 and its species should be — 



4. E. tridciltatUS (Gairdner) Gill. 



It ranges from Monterey to Vancouver's Island, and Nos. "5" and 

 '^6" are not distinct from it. 



On page 8, after Ammocoetes pluinheus, add: 



7 {b). A. aureus Bean. 



Plumbeous above, golden yellow below; under side of head and neck 

 silvery. Maxillary tooth single, bicuspid; mandibulary with 7 cusps, 

 the outer largest. Head shorter than chest; distance from eye to first 

 dorsal thrice base of first dorsal; base of second dorsal twice as long 

 as that of first, the fin twice as high; interspace between dorsals § 

 length of head; tail (from vent) 4 in total length. Head lOJ {5^ in 

 distance to first dorsal). L. 15 inches. Yukon Eiver, Alaska; abun- 

 dant. (Bean.) 



{Ammocceies aureus Beau, Proc. U. S. Nat. Miis. iv, 1881, 159: '^ Petromyzon viarinus 

 camtschaticus Pallas, Zoogr. Rosso-Asiat. iii, 1811.) 



On page 9, after Ammoccetes niger, add: 



8 (b). A. appeaidix (Dekay) Gill. 



Dusky brown, sometimes tinged with bluish; fins pale amber. A 

 ring of irreguiarly-shaped corneous processes within the mouth, aud a 

 large isolated double tooth of the same texture on the inferior portion 

 of the mouth. Origin of dorsal in advance of middle of body (behind 

 middle in A. niger). Vent near posterior third of body. Anal papilla 

 (•'appendix") conspicuous in males in spring. Streams of l!^ew York 

 and Southern New England. {DeMy.) Not lately recognized, but ap- 

 parently differing from A. niger in the less posterior dorsal. 



{PeU-omyson appendix Dekay, New York Fauna, Fish. 1842, 381: Ammoca-tes anieolor 

 Dekay, 1. c. 383; larva. Of the remaining speciea described by Dekay, Ammococtes 

 bicolor Le Sueur, 1. c. 383, seems to be the larva of Petromyzon marinus, aud P. lamot- 

 teni Le Sueur MSS. 1. c. 882, is probably Petromyzon argenteus.) 



Page 10. Petromyzon castaneus has been lately received from Loui- 

 siana. It is considered a valid species by Dr. Bean, as is also 9 (6), 

 P. hiriido (Grd.) Bean. Both these species have the maxillary tooth 

 tricuspid, not bicuspid as in P. argenteus. 



Page 11. The mandibulary teeth in Petromyzon marinus are usually 

 7 in number. The plates of the anterior lingual pair are confluent, and 

 not their serrations as stated in the text. 



