504 PETEOltrZONXIDiE. 



in the circumference of the suctorial disk. This, again, is not confirmed 

 by the examination of examples. In all of them I count seven points 

 only, and the small suctorial teeth are as distinct as in P. Jluviatilis. 

 The examples of P. omalii are generally a little stouter in general 

 habit than large and full-grown individuals of P. Jluviatilis ; but this 

 is not a specific character, as the indi\aduals, not only of this species 

 but also of P. marinus, vary very much in this respect. 



Petromyzon japoiiicus, Martens, Wiegm. Arch, xxxiv. p. 3, does 

 not appear to me to be specifically distinct from P. Jluviatilis. The 

 dentition in both is extremclj' similar, only the Japanese example 

 has an additional transverse scries of small teeth behind the mandi- 

 bulary tooth. The figure accompauying the description of P. ja- 

 ponicus is incorrect, and I am indebted to Prof. Peters for reex- 

 amination of the typical specimen. 



3. Petromyzon branchialis. 



Pride, Sand-piper. Small Lamprey. 



a. Ammocoetes-form. 



Lamproyon on Lamprillon, Rondel. De Pise. Fluv. p. 202. 



Lampetra caeca, Willughhy, p. 107, tab. G ?>. fig. 1. 



Petromyzon, no. 3, Artecli, Synon. p. 90, and Gen. p. 64 ; Gronov. 



Zoophijl. p. 38. no. 3(i0. 

 Petromvzon branchialis, Z. Siist. Nat. i. p. 394 ; Bl. Fisch. BeutschL 



iii. p.43, taf. 78. fig. 2 ; Bl. Schn. p. 532 ; Lacep. i. p. 2^, pi. 2. fig. 1 ; 



Tint. Brit. Faun. p. 110; Gronov. Si/sf. ed. Gray, p. 2. 

 Pride, Penn. Brit. Zool. iii. p. 71, pi. 8, or,ed. 1812, iii. p. 107, pi. 10. 

 Petromyzon ruber, Lacep. ii. p. 99, pi. 1. 



lumbricalis. Pall. Zooyr. Ross. -As. iii. p. 09. 



cfecus, Couch, in Loud. May. Nat. Hist. v. p. 2."., fig. 10. 



Ammocoetes branchialis, (Dumeri!) Cuv. Riyne An.; Niks. Skand. 



Faun. Fisk. p. 748 ; Flcm. Brit. An. p. 164 ; Jenyns, Man. p. 522; 



Parnell, Fish. Firth of Forth, p. 287; Yarrell, Brit. Fish. 2nd edit. 



ii. p. 609 ; Selys-Lonychamps, I^aune Belye, p. 227 ; Kriiyer, iJanm. 



Fisk. iii. p. 1060; Giinth. Fisch. Neckar's, p. 135 ; Meckel S,- Kner, 



Siisswasserf. p. 382, fig. 204 ; Grai/, Chondmpt. p. 145. 

 Mud-Lamprey, Couch, Fish. Brit. Isl. i. p. 404, pi. 248. fig. 2. 



/3. Mature form. 



Petromvzon planeri, Bl. Fisch. Beutschl iii. p. 47 [taf. 78. fig. 3 ?] ; 



Bl. Schn. p. 531 ; Lacep. i. p. 30, pi. 3. fig. 1 ; Osheck, Vet. Akad. 



Handl. 1804, p. 181; Blainv. Fuune Fran(;. ii. p. 8, pi. 1. fig. 3; 



Jenyns, Man. p. 522 ; Yarrell, Brit. Fish. 2nd edit. ii. p. 607, or, 



3rd edit. i. p. 10 ; Parnell, Werner. Mem. vii. p. 446 ; Nilss. Skand. 



Faun. Fisk. p. 747; Selys-Lonychamps, Faune Belye, p. 226; 



Kriiyer, Danm. Fisk. iii. p. 1060; Giinth. Fisch. Neckar's, p. 135; 



Heckel 8f Kner, Siisswasserf. p. 382, fig. 204; Avy. Miiller, in 



Midler's Arch. 185(), p. 325; Siehold, Siisswasserf. p. 375; Couch, 



Fish. Brit. Lst. iv. p. 402, pi. 248. fig. 1 ; Blanchard, lUss. France, 



p. 517 ; Canestriui, Arch. p. la Zool. iv. p. 186. 



uiger, LjAcep. iv. p. 667, pi. 15. fig. 2. 



septoeuille, iMcep. I. f. fig. 1. 



•" — sanguiduga, Ljucep. ii. p. 101. 



