274 



BULLETIN OF THE BUREAU OF FISHERIES, 



Armature of skin. —Skin in the young smooth; in larger examples small tubercles are present along 

 median line of back and a row of three or more on each shoulder; later small spinules are scatteringly 

 present on shoulders and interorbital space; in very old examples region adjacent to median line of 

 back is thickly sprinkled with small spinules, these are also present on the tail immediately in front 

 the spine and along the sides of the tail behind the spine. 



Measurements of a Male (No. i) no. 5 Cm. (43.5 Inches) Long from North River, Sept. 17, 1912, 

 AND A Female (No. 2) 155 2 Cm. (61. i Inches) Long from Fort Macon, Aug. i, 1913. 



No. I. 



No. a 



Tip of snout to posterior edge of pectoral 



Tip of snout to posterior axil of pectoral 



Tip of snout to base of spine 



Breadth of di»k .*. 



Length of anterior margin of disk 



Length of posterior margin of disk 



Tip of snout to anterior margin of orbit 



Horizontal diameter of eye 



Interocular space 



Tip of snout to — 



Front of mouth 



Inner angle of first gill slit 



Inner angle of second gill slit 



Inner angle of third gill slit 



Inner angle of fourth gill slit 



Inner angle of fifth gill slit 



Interspace between anterior gill slits 



Interspace between posterior gill sUts 



Tip of snout to vent 



Length of ventrals 



Length of claspers 



Breadth of claspers 



Breadth of mouth y 



Disk quadrangular; anterior margins nearly straight, meeting in an obtuse angle at tip of snout; 

 posterior margins of disk slightly rounded, posterior angle rather sharp: ventrals projecting but little 

 beyond the disk; tail with a low median keel on top behind the spine and a long cutaneous fold below. 



When landed in the seine the female gave birth to three young, two females 40 and 51 cm. long and 

 a male 48 cm. long. These were similar in form to the adult, upper surface devoid of tubercles. 



The disk and ventrals are narrowly margined with white, with an intramarginal area of dark colora- 

 tion, shading into body color; in adults there is a small gray or white spot on median line of snout 

 immediately in front of eyes; sides of tail white or grayish; keel and fold of tail black. The ground 

 color of these rays changes with change in color of background. 



The females examined had been feeding on clams, shrimps, marine worms, and small teleosts. Males 

 examined had eaten shrimps and blue crabs. An attempt was made to determine whether there was a 

 selective difference between the sexes in the character of food which might throw some light on the 

 differences in the form of the teeth, although several females, but none of the males examined, had been 

 feeding on clams; sufficient material has not as yet been examined to be of value. No pieces of shell 

 were present with the clam meat. 



This species is common in the harbor, especially in North River. That their feeding habits attract 

 them to regions where clams and oysters are to be found seems certain. 



28. Dasybatus sabinus (Le Sueur). Sting ray. 



Dasyatis sabina. RadcUffe. 1913, p. 396. 



Teeth. — Teeth similar in form and coloration to D. haslatus;m a male 69.6 cm. long they are in about 



— rows; in a female (length of disk 39 cm., tail mutilated) in about — rows; upper teeth larger than the 



lower; upper jaw more strongly arched than in either of the other species of Dasybatus. 



Armature of skin.^Sidn in very small examples smooth, later a median row of sharp tubercles 

 appears; in larger examples these extend as far back as spine and one or more tubercles appear on each 

 shoulder; in adults the interorbital space is thickly sprinkled with small spinules; these are scatteringly 

 present on the shoulder region in old individuals. 



