AGONIDA. — LXXIV. 151 
depth 6. D. VIT-18. A. 15. V.I,3. L. 3. Deep waters of 
L. Michigan and L. Ontario, (To Rev. Zadock Thompson, author 
of Nat. Hist. of Vermont.) 
191, TRIGLOPS Reinhardt. (rplyAa, Trigla; dy, appearance.) 
419. T. pingeli Reinhardt. Head slender; eye large; tail very 
slender; preopercular spines small, simple; sides with peculiar 
scales and prickles. Olivaceous, variegated with darker; sides 
spotted with dark ; a black ocellus on spinous D. Head 3}; depth 
about 54. D.ITX-21. A. 21. L.5. Arctic seas, 8. to Cape Cod. 
192, GYMNACANTHUS Swainson. (yupvds, naked ; 
dxavOa, spine.) 
420. G. tricuspis (Reinhardt). Eye very large; skin mostly 
smooth ; preopercular spine broad, shorter than eye, with 3 
points; V. very long. Dark brown with darker bars; axils dusky 
in # with round white spots. Head 34; depth 4%. D. XII-16. 
A. 18. V.I,3. L. 12. Arctic, 8. to Me. (E£u.) (Lat., iris, 
three ; cuspis, cusp.) 
Famiry LXXIV. AGONIDAK. (Tue ALLIGATOoR-FISHES.) 
Fishes allied to the Cottide and similar in general structure, but 
with the body completely covered by a coat of mail composed of 
about eight series of large bony plates; head entirely bony exter- 
nally; suborbital stay covering the cheek; gills 34, no slit behind 
the last, pseudobranchie large. Vertebre (as in other Arctic 
fishes) numerous, 35 to 40. Spinous dorsal sometimes wanting. 
Small fishes, chiefly of the Arctic seas; genera 10, species about 
20. (a, privative ; yovia, joint; 7. e., rigid.) 
u. Spinous dorsal obsolete; gill membranes free from isthmus. (Aspidopho- 
roidine.) 
b. Bony plates keeled, without spines; fins very small; teeth on vomer. 
ASPIDOPHOROIDES, 193. 
193. ASPIDOPHOROIDES Lacépéde. (domis, shield; hopéw, 
to bear; eidos, form.) 
a. Snout with two large diverging spines above; no other spines present. 
421. A. monopterygius (Bloch). Body elongate, subterete, re- 
sembling that of a pipe-fish; eyes very large. Brownish, obscurely 
banded. Head 52; depth9. D.5. A.6. Lat.1.50. L.6. Cape 
Cod, N. (ydvos, single ; mrépvé, fin.) 
Famity LXXV. CHPHALACANTHIDA. 
(THE Fryine Gurnarps.) 
Body elongate, with bony keeled scales; head blunt, cuboid, its 
surface almost entirely bony; nuchal shield with a strong spine on 
