98 TELEOSTEI : PERCESOCES. — XIX. 
no dermal plates, the bones and spines all feeble; tail keeled. Head 
34; depth 4. D. IV-J, 10. A. I, 10. L. 24. N. Y. to Kansas 
and Greenland, abundant N. W. in small brooks; S. to Greensburg, 
Ind. (Shannon.) Var. cayuga Jordan (W. N. Y.) has V. spines 
longer, longer than innnominate bones, and other trifling differences, 
110. GASTEROSTEUS (Artedi) Linneus. 
(yaornp, belly; éaréov, bone.) 
uw. Sides partly covered with bony plates, the tail naked. 
b. Lateral plates 2 to 7. 
c. Ventral spine without cusp at base; lateral plates 2 or 3. 
240. G. wheatlandi Putnam. No mucous pores; tail com- 
pressed. Blackish. D. IJ, J, 10 to 12. A. 1,8. Cape Cod, N. 
scarce. (To Dr. Richard H. Wheatland, of Salem, Mass.) 
cc. Ventral spine with a strong cusp at base behind; lateral plates 
about 7, 
241. G. gymnurus Cuvier. Tail keeled. Grayish, dotted. 
D. II, J, 12. A. I, 8 L. 24. Newfoundland to Greenland, etc. 
(G. dimidiatus Reinhardt.) (Eu.) (yupvds, naked; odpd, tail.) 
66. Lateral plates 15; tail keeled. 
242. G. atkinsii Bean. Slender; V. long. Head 3}; depth 5. 
D. IT, 1, 11. A.J, 8 L. 14. Maine. (To Charles G. Atkins, 
Fish Commissioner of Maine.) 
aa. Sides entirely covered with (28 to 33), bony plates; tail keeled; V. spine 
with cusp at base. 
243. G. aculeatus L. Common StickLeBacx. Olivaceous, 
sides silvery; back dotted; opercles striate; rugose plates at. base 
of spines; spines serrate. Head 3}; depth 44. D.II[-I,13. A. 
I,9. L.4. N.Y. to Greenland and Europe, abundant, variable. 
(Eu.) Perhaps all the preceding are forms or varieties of this. 
(Lat., bearing prickles.) 
lll. APELTES DeKay. (a, privative: wéArn, shield. 
244. A. quadracus (Mitchill). Olive, mottled; males nearly 
black, the V. red in spring; body plump, with long slender tail; 
skin naked. Head 4; depth 4. D. III,I,11. A. 18 L.2, 
N. J. to Labrador ; abundant along coast. (Lat., four-spined.) 
Orprr XIX. PERCESOCES. 
This group comprises Physoclysti, which have the general char- 
acters of the great group of Acanthopteri, but in which the ventral 
fins are abdominal, the pelvic bone not being attached to the 
shoulder-girdle. Scales cycloid, opercles unarmed. The spinous 
dorsal is short and sometimes (Ophiocephalide) wanting. (Lat., 
