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148 Gudgei — Notes on Some Beaufort, N. C., Fishes. 



Pteroplatea maclura (Le Sueur). 



BUTTERFLY RAY. 



In making observations and collecting data for a study of viviparity in 

 the butterfly ray, the writer was so fortunate in 1910 as to get a good 

 amount of embryonic material, in fact fully half the stages necessary for 

 the life history. The most interesting of these is a young ray with the 

 pectorals so far developed that they have coalesced with the head stalk, 

 with long, filamentous gills projecting from the gill slits, and, what is 

 most remarkable, with a tail nearly equal to the length of the body and 

 having its hinder two-thirds expanded into a broad paddle-like fin.* 

 When it is remembered that the adult ray has a very short and insignifi- 

 cant tail utterly devoid of any fin structures, the importance of this dis- 

 covery in the phylogenetic history of the animal is apparent. 



The writer's earliest collecting in 1910 was done on May 27. The uteri 

 of the first ray caught on that day were both pregnant, one egg being 

 found in each. These eggs each had a thin straw-colored transparent 

 shell much crinkled and plaited (bellows-fashion) at the ends but not 

 twisted as in the eggs noted in my paper for 1900. One end of each shell 

 was long and clear, the other end short and crushed, — "telescoped " is 

 the way the notes put it. One egg had a selachian embryo, the other an 

 invaginating blastoderm . 



Waite (11(01, 1902) quotes letters from Haswell that the viviparous 

 Hemiscillium modestum has around its egg a thin shell which is soon 

 thrown oft', and that Galeus antarcticus has chitinous bodies in the uterus 

 consisting, as proved by chemical analysis, of the identical material as 

 that composing the egg shell of Cestracion and of other viviparous Elas- 

 mobranchs. These bodies Haswell considers as several vestigial shells 

 run together. Later, Waite (1909) took several female GaJeus australis, 

 of the family Carchariidae, in which were found numbers of young, each 

 in a thin membranous envelope contained within the uteri. One female 

 contained 34 young equally divided between the 2 uteri. t Parker and 

 Haswell (1897) on p. 108 of Vol. II say: "In some of the viviparous 

 forms (of Elasmobranchs) a distinct, though very delicate, shell, some- 

 times having rudiments of the filaments, is formed, and is thrown off in 

 the uterus." The chalaza-like structures, seen by the present writer in 

 lV)09-'10-and '11, were in all probability these vestigial filaments. These 

 structures have been described above for the bonnet-head shark also. 



The uteri of every one of these rays, as in Dasyatis say, had the interior 

 villous, and all save three were filled with milk. Two of these, opened 

 as soon as the female was caught, were enormously distended with a clear 

 liquid which showed no signs of milk, while the third, after being in 

 formalin some hours, was found to have a buttery precipitate in a clear 

 supernatant fluid. There can be but little doubt that the purpose of the 

 long external gills is to absorb this " milk " and that after the disappear- 



* See Gudger (1911) for an abstract of a report on this larva made before the N. C. 

 Aead. Sci. 



t See also Aleoek (1901) as Quoted in my Notes for 1909 (Gudger, 1910). 



