\ 



10 CONTRIBUTIONS TO NORTH AMERICAN ICHTHYOLOGY - IV. 



;he lai-e bnccal disk, the maxillary teeth being pointed, two in number, 

 8Cl dose i".u< 'Hi. T. witln -ut interspace, and not ionning a crescent -shaped 

 ].latc; lateral teeth all nnicnspid ; mandibulary with IIUIIMVOU> close- 

 pointed cusps, appearing like dist inet teeth ; lingual teeth in two 

 serie>. the posterior series linely pectinate, with a median suture dividing 

 it int.. a ri-ht and lei't cres.-eiit >haped comb; anterior series not divided : 

 I In- pectina'coale.M-eni. This genus is most nearly ivla led toPetromyzon, 

 dill'i-ring chietly in the eontinnons dorsal. The two known species in- 

 habit tin- Mississippi Valley and the Great Lakes. (yOu;, fishj nb'w, to 

 suck.) 



- M.indilnilary i>laU- with seven teeth. 

 9. I. artfClltCUS (Kirt.) Gnl. *'<lr<ri/ Lamprey. 



Body stoutish, compressed behind; head broad, with large buccal 

 disk, which is fringed, but not very conspicuously; teeth pretty strong 

 and nearly uniform, the two maxillary teeth being very similar to those 

 on the. rest of the disk; niandibnlary teeth conuivent, the middle ones 

 the longest ; upper margin of dorsal scarcely depressed in front of the 

 vent. Color bluish; sides silvery, often mottled; a small dusky spot 

 above or nearly above each gill-opening, usually conspicuous. L. 12. 

 Great Lakes and Mississippi Valley ; rather common ; ascending small 

 brooks in the spring. 



(l',lr,>iii!i:<>ii <ir<!< ,,t<;ix Kirtland, Bost. Journ. Nat. Hist, iii, l-\". -I.', with plate. 

 .InniKH-iiti'x i-<,n<-i>li- Kirt. 1. c. 4?:5, with ]>latr. /C/I//M/<>/;M/:/I ttinnlii (!nl. I'ar. \i. R. 

 Sins . ::].'. Irlill,i/i>ini/~on liirudo Gthr. viii,rj()7. .lnnn<n'ii If* uri/nilnix i-t hirmh Jurdaii, 

 50. -Ammoocetes <rj>upl<ra Abbott, Proc. Ac. Nat. Sci. Phila, I860, 3:27.) 



1. 1 IK I Unitary jilate with nine trHh. 

 1O. I. rastUllCllS Gnl. Cln-xtnnl-nihtrnl Lillil]-i I/. 



Lips with short fringes; dorsal fin high, with a de]>ression in front of 

 the \ent. A little known species, differing from the preceding, if at all, 

 in the number of teeth on the mandibulary plate. Minnesota. 



(/r/i//i//n)/ii/;iii/ I.X//;K//S i ii-il. I'ac. li. li. Surv. o.Sl.) 



7. PETUO.tlYZORT Linuajus, 1758. 

 Sea 



(Arti-di Linna-iH. S\>lrma Natura-; typr l'ctri>i>i;un inarinux L.) 



Lainpre\ s of medium or large si/e, \\ it h the maxillary teeth separate, 

 pointed, and clo>r to-rther, not forming a crescent -sliaped jdate; man- 

 (libiilai-\ plate \\iih seven to nine cusps; lingual teeth forming two 

 crescent >haped plates on each side; first dorsal tin well separated from 



