1030 REPORT OF COMMISSIONER OF FISH AND FISHERIES. [50] 



acteis wliicli have been supposed to differentiate Molacanthus as the 

 type of a family, subfamily, genus, or species distinct from Mola has 

 the slightest taxonomical value, and much as the writer would desire 

 to agree with Dr. Gill's* views in relation to these matters, he is forced, 

 after carefully weighing all of the evidence before him, to arrive at 

 a conclusion directly opposed to that of the above-mentioned distin- 

 guished authority. 



That the little fish described by Sir J. Richardson t as '■' Ostracion 

 hoops''^ is in all probability the young of some form of Mola^ or of a 

 type closely allied, cannot be questioned, from the fact that the spines, 

 while not as numerous as those distributed over the skin of the Mola- 

 canthus stage, yet agree to a certain extent with those on that form 

 in their relative position, and also in the fact that they, as in the latter, 

 have raised carina radiating from their apices, which are surmounted 

 by rows of diminutive secondary spines. Certain it is at any rate that 

 the form is not an Ostracion, because the two x^osterior fins are mani- 

 festly to be regarded as anal and dorsal, and not as " anal and caudal," 

 as supposed by Eichardson, for his figure 21 shows that there is a nar- 

 row interval between these two fins which is the homologue of the in- 

 terval between the two corresponding fins of the Molacanthus stage. 



Richardson's description of ''0. hoops'''' may be profitably reproduced 

 in this connection : 



"Radii : C. [D.] 12; A. 14 5 P. 14 (Dr. Hooker). Being unwilling that 

 any of the novel forms of fish sketched by Dr. Hooker should be alto- 

 gether lost to science, though the specimens from which they have been 

 designed have peiished, we here i)resent an Ostraciou, in which the 

 chief novelty appears to be the want of a dorsal fin. Dr. Hooker has 

 given four views of this little fish in different positions, viz : [PI. XXX, 

 fig.] IS, a lateral view, [fig.] 19, a view of the back, terminated at each 

 end by a long spine, and with two smaller intermediate eminences, 

 which seem to replace the dorsal fin. Fig. 20 shows the under surface, 

 when the fish is turned so as to bring the mouth and frontal spine into 

 view, and [fig.] 21, the posterior surface, looking from the vent over the 

 anal and caudal [dorsal] fin to the long caudal spine. 



"iZaft. — Taken in the Southern Atlantic in a tow net." 



It is not stated in the original description by Richardson how much 

 the figures are enlarged, but Gunther says (Introduction to the Study of 

 Fishes, p. 175) that Richardson's figure 18, which we have reproduced 

 in the accompanying Plate VIII, Fig. 1, is "much magnified;" informa- 

 tion which he may probably have obtained from Dr. Hooker himself. 

 The great size of the eye would also indicate that the specimen was 

 very young, and would lead the writer to think that the figure must have 

 been drawn considerably larger than natural size. The front and top 



* Synopsis of the Plectognath Fishes. Proc. U. S. Nat. Mus., 1884, 411-429. 

 tVoy. Erebus and Terror (Ichthyology), p. 52, PI. XXX, Figs. 18-21. (Drawn by 

 Dr. Hooker.) 



