488 CONTRIBUTIONS TO NORTH AMERICAN ICHTHYOLOGY IV. 
latter bearing a strong external resemblance to the UtJieostomatincc, and 
serving as a connecting link between them and the more typical forms. 
(PcrcUhv i):irt, Giiiither, i, 58-78; ojenera Perea, Lucioperca, Fileoma, Bohoeoma, Ace- 
rina, Pt-rcarina, Asjyro, Fcrc^chfhi/s, aud FerejUa.) 
* Anal spines one or two. 
a. PseiulobranchiiB imperfect or wanling; preoiiercle entire; Ijrauchiostegals G. (Ethe- 
osiomalinw.) 
i. rremaxillaries protractile. 
c. Body extremely elongate, snbcylindrieal, translncent, tlic belly at least naked; 
lateral line complete; gill-membranes broadly united. 
(7. Anal spine single ; anal tin nearly as large as second dorsal. 
Ammocrypta, 252. 
dd. Anal spines two; anal fin small Ioa, 253. 
cc. Body less elongate, opaque, cliiefiy scaled. 
e. Anal spine obscure, normally single. 
/. Lateral line complete, or wanting on a few scales only . . Boleosoma, 254. 
ff. Lateral line incomplete Vaillantia, 255. 
ee. Anal spines tAvo, the first commonly the longer. 
(j. Gill-membranes more or less broadly united ; belly with ordinary scales. 
h. Maxillary bone normal Ulocextra, 25G. 
hi). Maxillary adnate to the preorbital Diplesium, 257. 
f/g. Gill-membranes scarcely connected. 
i. Belly Avitb enlarged caducons plates Cottogaster, 258. 
ii. Belly without enlarged caducous plates Imostoma, 259. 
hb. Premaxillaries not protractile. 
j. Lateral line complete. 
Jc. Ventral line with a scries of enlarged, spinous, caducous scales 
or (if these are fallen) a naked strijA. 
1. Mouthsmall, inferior, beneatha pig-like snout .. Percin A, 2G0. 
77. Mouth larger, the snout not projecting beyond it. 
Alvorpius, 2G1. 
kk. Ventral line w ithout caducous scales. 
m. Gill-membraues scarcely connected. 
n. Anal fin larger than second dorsal Hadiuapterus, 282. 
nn. Anal fin smaller than second dorsal . .Ncathonotus, 2G3. 
mm. Gill-membranes broadly connected .. .Naxostoaia, 2o4. 
jj. Lateral Hue present, incomplete. 
0 . Gill-membranes broadly united Etiieosto.aia, 265. 
00 . Gill- membranes separate or nearly so. 
PCECILICIITIIYS, 286. 
jjj. Lateral line obsolete Microperca, 2G7. 
aa. Pseudobranchiai well developed ; ])reo])ercle serrate; branchiostegals7. ( crcina\) 
J). Canine teeth none; body oblong Perca, 2G8. 
pp. Canine teeth in jaAA's and palatines; body elongate. 
SXIZOSTEDIUAI, 269. 
252.— AMMOCISYFTA Jordan. 
Sand Darters. 
FIcuroJepis Agasiiz] not Fleurolcpis 'Egevton, a genns of extinct Ganoids.) 
(Jordan, Bull. U. S. Nat. Mus. x, 6, 1877 : type Ammocrgpta &cani Jordan.) 
Body slender and elongate, sub-eylindrical ; pellucid in life. Head 
* Agassiz, Bull. Mus. Comp. Zool. i, 5, 1863: type Etheostoma pcUiicidum Bainl MSS. 
