Teacher:Given a text passage, you need to generate a suitable title as the output. The output title should be one of the words/phrases used in the passage and must be no longer than five words. 
Teacher: Now, understand the problem? Solve this instance: Paragraph:    The pectoral fin disc of the plain maskray is thin and diamond @-@ shaped with narrowly rounded outer corners , measuring 1 @.@ 1 – 1 @.@ 3 times longer than wide . The leading margins of the disc are gently concave and converge at a broad angle to the pointed tip of the snout . The small eyes are placed close together , and behind them are the spiracles . The nostrils are elongated and have a skirt @-@ shaped flap of skin between them . The small mouth bears prominent furrows at the corners and contains two slender papillae on the floor . Small papillae are also found around the outside of the mouth . There are five pairs of gill slits . The pelvic fins are fairly large and pointed . 
 The tail is short , barely exceeding the length of the disc when intact , and has a broad and flattened base leading to usually two stinging spines . After the stings , the tail becomes slender and bears a long ventral fin fold and a much shorter , lower dorsal fin fold . Most of the body lacks dermal denticles ; a midline row of 4 – 13 small , closely spaced thorns is present behind the spiracles , and another row of 0 – 4 thorns before the stings . The dorsal coloration is grayish green , becoming pinkish towards the disc margins ; there is a dark mask @-@ like shape around the eyes and a pair of small dark blotches behind the spiracles . The tail behind the stings has alternating black and white bands of variable width , ending with black at the tip . The underside is plain white and the ventral fin fold is light grayish in color . This species grows to 24 cm ( 9 @.@ 4 in ) across and 45 cm ( 18 in ) long .   Question: what is the suitable title of the passage ?
Student:
Description