272 Papers from the Marine Biological Laboratory at Tortugas. 



bonasus, S}^ inches long by 133^ wide. Bleeker has in the same way 

 obtained the young of R. javanica 20 inches wide. Later (Gudger 1912A) 

 the writer captured by seining young R. bonasus only 13 inches long. There 

 is but little difference in size between the adults of these two rays, this, if 

 any, probably being in favor of Aetobatus. If it is agreed that the fish noted 

 in the preceding paragraph are young, then attention is called to the fact 

 that all were normal in coloring, mine all having spots over the whole 

 dorsal surface. 



GiJnther (1910) corroborates this by his description of a young male 

 from the South Seas, which measured 11 inches (long presumably) and 

 whose tail was 43 inches long. Its whole upper surface was beset with 

 round spots, a few being found on the head. However, Cantor (1849) 

 had a young specimen from Indian waters which was only 73^ inches long 

 by iiM wide with a 2-spined tail 33^ inches in length. This was greenish- 

 olive or greenish-gray above and lacked spots on the head and anterior 

 margin of the pectorals. Likewise, Day (1878) writes that in the young 

 of the Indian form, in which the greenish-olive or leaden-gray adults have 

 the body usually covered with numerous dirty-white or bluish spots, the 

 back is of a deep leaden color and the spots are hardly apparent. 



Annandale (19 10) tells us that the very young specimens of A. narinari 

 are either unspotted or have spots just beginning to appear, thus corroborat- 

 ing Cantor and Day. He had two Indian specimens whose respective 

 measurements were: breadth 23.2 and 20.4 cm.; length 13.7 and 12.4 cm.; 

 and whose tails measured 57 and 47.5 cm. long. His fine figure of the larger 

 of these young males is reproduced herein as figure 17, plate vii. It is 

 entirely devoid of spots, whereas both Jordan's smallest specimens and 

 mine also were beautifully marked. 



Klunzinger (1871) is the only student of this ray who has obtained 

 an unborn young, and he contents himself with saying that it measured 

 12 centimeters. At Cape Lookout, in 1912, Coles (1913) was so very 

 fortunate as to witness the giving birth to several young by a female 

 which he had just caught. These young were uniformly spotted all over 

 the body, the spots being fewer in the head region; these may be seen 

 in figures 9 and 11, plate v, while figure 18, plate vii, is a photograph of 

 one of these young taken after some months' preservation in formalin or 

 alcohol. It will be noticed that the spots are much fainter and seemingly 

 fewer in the preserved specimen. This particular little ray was 286 mm. 

 wide, 171 mm. long, while its tail measured 634 mm. 



The question of the presence or absence of lines or bands across the 

 dorsal surface of the spotted eagle ray is a most interesting and puzzling 

 one. They are sometimes present, usually absent; they are sometimes 

 bands, generally lines when present at all. In connection with the de- 

 scription of one of the specimens from Florida, an explanation of the lines 

 on its dorsum has been given (page 269). They are due to the presence 

 between the skin and the flesh of canals filled with liquid, possibly blood. 



