f J/cfo-cCus C7Ctr-hocfeu.,fi-$. 3 - <$crtidro-KuJcyjMtx. t<j Sp^BZf. ' » 
' |b/. mV. I- c, . LJ S’ r *’CTinn<. 
P /UePcfnS^, f /I* 3'<*■*“**&** '9*4’°'/’ 'tf, /> // ’-f y 9 5 ' 
PTTCTODONTID^l. f 39 
The following species are recognized :- 
y x/x/Xj^. s3a 
/74>r^»^‘''p*7 
Ptyctodus calceolus , J. S. Newberry, Eep. Geol. Surv. Ohio, vol. ii. ~ 
- /naJU jpt. ii. (1875), p. 59, pi. lix. fig. 13 : Rinoclus calceolus, 
/ wherry & Worthen, Pal. Illinois, vol. ii. (1866), p. 106, 
^ j ^ $3' pl.x. fig. 10.—Hamilton Group (Upper Devonian); Illinois 
3 Y ’*' an ^ I° wa - [Abraded tooth, the type species of Rinodus.~\ 
^ S yu ~ r ’ p t y doc i us 0 Uiquus, C. H. Pander, Ctenodipt. devon. Syst. (1858), 
/ /'^y>.^zpU64, pi. viii. figs. 1-9, 11, 13-22 : Ptyctodus ancinnatus , 
jf. icJJ-^ C. H. Pander, ibid. p. 64, pi. viii. figs. 10, 12 : Aulacosteus 
/? 23,/°*-''' cochlear iformis and A. oviformis , E. von Eichwald, Leth. 
fy* Eossica, vol. i. (1860), pp. 1548, 1550, pi. lvii. fig. 8.— 
Middle Devonian; Governments of St. Petersburg, Nov¬ 
gorod, and the Baltic Provinces. [Abraded teeth ; School 
of Mines, St. Petersburg. The type species.] 
RHYNCHODUS, Newberry. 
^ [ Re P- Geo1 - Surv - 01 “°, to1 ‘ i- pt ' 18 ' 3 ’ p ' 30 ^J ~Zfa* 
In the type species of this genus, four teeth have been found 
associated in a group, suggesting that those of the upper and lower 
jaws were similar, a single pair occurring in jsacln^ n i J- <?"^ c A 
/>avS ~?S,ph - ft- 6 U-b<? 
The following species are known :— friths /r ^' 
Rhynchodus excavatus, J. S. Newberry, Eep. Geol. SurvAVisconsin, 
33 
A ; (Mon. U.S. Geol. Surv. no. xvi. 1889), p. 50, pi. xxix. 
-* Z 6 "" “ £? ~ 1 -Hamilton Group (Upper Devonian) ; Milwaukee, 
vol. ii. (1877), p. 397, and Palaeoz. Eishes N. America 
h-^7’ 
V^x^«V _g^ nc hoclus occidentalism J. S. Newberry, Ann. New York Acad. 
Sci. vol< ( 18 ^ 8 )> P- 192.—Hamilton Group; Iowa. 
[Columbia College, New York.] 
Rhynchodus secans , J. S. Newberry, Eep. Geol. Surv. Ohio, vol. i. 
£ , pt. ii. (1873), p. 310, pi. xxviii. fig. 1, pi. xxix. figs. 1, 2, 
'hu — and p^geoz. pishes N. America (1889), p. 47, pi. xxviii. 
figs. 1-3.—Corniferous Limestone...(Middle Devonian) ; 
Ohio. [The type species, Columbia College.] 
Rhynchodus , sp. ind. : Physichthys hoeninghausii, H. von Meyer, 
Pakeontogr. vol. iv. (1855), pi. xv. fig. 9 {errore ).— 
Devonian; Eifel, Germany. [Museum of Comparative 
Zoology, Cambridge, Mass.] 
Genus PALiEOMlfLUS, nov. 
In the type species of this genus (P. frangens) the symphysis is 
as broad as in Edaphodon. 
'9 JV 
