PLATE 61. 



PLATOSOMIA and ANTACEA. 



Fig. 1-3. Narcacion marmoratus (Page 305). Fig. 4-5. Narcacion nobilianus (Page 310 

 Fig. 6. Narcine timlei (Page 300). Fig. 7-8. Chlamydoselachus' anguineus (Page 14). P^ 

 9-11. Rhina californica (Page 253). 



1-3. Various stages from De Sanctis, 1872. 



4-5. Four fifths and natural length. M. C. Z. 1016. 



6. One and two thirds natural length. 



7-8. One and three fourths natural length. M. C. Z. 1285. 



9-10. Five sixths natural length. M. C. Z. 916. 



11. Two and two thirds natural length. M. C. Z. 916. 



The first three figures illustrate the squaliform raiiform and torpediform stages socalled by ij 

 Sanctis (1872, Atti Reale accad., 5, pi. 1, fig. 3, 6, 9.) In fig. 3 the forward extension of the pectorals, 

 the sides of the batteries, is strongly marked while the lateral growth of the antorbital process ultimattj 

 forming the front of the disk has hardly begun; at this stage the latter merely forms a pad in front of tj 

 head. Figures 4 and 5 from a specimen off the coast of New England illustrate the lateral growth of tj 

 antorbital portions of the disk to meet the forward extensions of the pectorals and, with the obliteratij 

 of the notch opposite each eye, complete the disk. See the skeleton of N. marmoratus on Plate <l 

 ao. The batteries are well developed and the disk completely outlined at a very .small stage of iVarcil 

 timlei, fig. 6. In connection with fig. 7-8, showing the yoimg Chlamydoselachus with well differentiajj 

 fins and external gills, see also fig. 4-5, Plate 59. The embryo of Rhina californica, fig. 9, was atta 

 to an enormous mass of yolk, longer and many times the weight of the little shark. Figures 10 an4 

 show the intestines and their connection with this yolk, the dotted lines indicating the entrance in f| 

 of the spiral folds. 



