FISHES OF CHESAPEAKE BAY 
69 
KEY TO THE GENERA 
a. Teeth in the jaws in several series; sides of head not entirely free from the pectorals; the 
rostral process and the pectoral fins narrowly confluent .. Myliobatis, p. 69 
b. Teeth in one row in each jaw; pectoral fins not extending along the sides of the head; the 
rostral fins entirely distinct from the pectorals Aetobatus, p. 69 
16. Genus MYLIOBATIS Cuvier. Eagle rays 
Disk broad, the outer angles acute; rostral process narrowly confluent with the pectorals along 
the sides of the head; teeth in the jaws in 7 to 10 rows, tessellated, the median ones broader than 
the lateral ones; tail long, slender, bearing on its basal portion a dorsal fin and one or more serrated 
spines; skin smooth or nearly so. 
23. Myliobatis freminvillii Le Sueur. Eagle ray; Bull-nosed ray; Sharp-nosed ray; Bull ray. 
Myliobatis freminvillii Le Sueur, Jour., Ac. Nat. Sci., Phila., IV, 1824, p. Ill; Rhode Island. Uhler and Lugger, 1876, ed I, 
p. 185; ed. II, p. 157. 
Myliobatis freminvillei Jordan and Evermann, 1896-1900, p. 89. 
Disk broader than long, the outer angles rather sharp, anterolateral margin slightly convex, 
the posterolateral margin broadly concave, length of disk 1.5 in its width; pectoral fins narrowly 
confluent below eyes with the rostral process, the latter broadly rounded with a slightly protruding 
median tip; head to first gill slit 4.85 to 5.1 in width of disk; distance from snout to vent 1.8 to 1.95; 
snout 2.1 to 2.35 in head; preoral length of snout 1.85; width of mouth 2.5 to 2.65; interorbital 
space 1.9; eye lateral, 1.95 in snout; spiracles quite as large as eyes and situated immediately 
behind them; nasorial groove extending to mouth; teeth in pavement about 9 transverse rows in 
upper jaw, 4 functioning, 10 transverse rows in lower jaw, 6 functioning; skin smooth; a prominent, 
serrated spine present behind dorsal; tail long, whiplike, 1.45 to 1.55 in total length; dorsal fin 
situated on tail, its origin at vertical from tips of ventrals; ventral fins rather broad, posteriorly 
convex, its base 1.75 in snout. 
Color grayish above, white underneath, the outer tips of the disk becoming dusky. Some- 
times reddish or reddish brown above, according to published accounts. 
Two specimens — a male and female — 355 and 368 millimeters (14 and 14j/£ inches) wide from 
tip to tip of disks, are at hand. The broad, pavementlike teeth obviously are constructed for 
crushing hard objects. The stomachs examined were empty, but, as suggested by the structure of 
the teeth, we learn from literature that the animal feeds on mollusks and various hard-shelled 
crustaceans (Sumner, Osborne, and Cole, 1913, p. 739). 
This ray is not common. It is little known by the fishermen, who report that it is taken only 
occasionally in pound nets in the southern parts of Chesapeake Bay. In September and October, 
1922, during five weeks collecting at Ocean View, Va., where numerous hauls were made with 
collecting seines and where 32 hauls of an 1,800-foot commercial seine were observed, only eight 
individuals were seen. The maximum width of the largest specimen observed was 34 inches and 
the total length was 5 feet. This appears to be about the maximum size attained by the species. 
Habitat . — Cape Cod to Brazil. 
Chesapeake localities. — (a) Previous record: “Chesapeake Bay” (Uhler and Lugger). (6) 
Specimens in collection: Lvnnhaven Roads, Va., pound net, July 17, 1916, and June 25, 1921; also 
observed at Ocean View, Va., in the fall of 1922. 
17. Genus AETOBATUS Blainville. Spotted eagle rays 
Disk broad, the outer angles acute; head prominent; snout narrower than head, produced; 
rostral fins separate from the pectorals and at a lower level on the sides of the head; teeth in a single 
row in each jaw, fused, the lower plate long; anterior nasal valves confluent; a median notch in the 
preoral flap; tail long, slender, bearing a dorsal fin and one or more serrated spines on its basal 
portion; skin smooth. 
