426 PROCEEDINGS OF UNITED STATES NATIONAL MUSEUM. 



MOLACANTHID^. 



SYNONYMS AS SUBFAMILY NAMES. 



=Molacantliinse, Gill, Cat. Fishes East Coast N. A., p. 57, 1861. 

 =Molacanthina% Jordan .$■• Gilbert, Syn. Fishes N. Am., p. 865, 1883. 



Moloidea with a much compressed vertically exiianded body (higher 

 than long), without a marginal posterior or caudal fin, or Interspinal 

 bones for its support, and with a short intestine "making but two 

 turns." (Putnam.) 



Pelagic fishes of very small size. 



MOLACANTHUS. 



SYNONYMY. 



=Molacanthn,s, Swainson, Nat. Hist, and Class. Fishes, &c., v. 2, pp. 195, 329, 1839. 

 =Pallasia, Nardo, Ann. Sci. Regno Lombard. Veuet., v. 10, p. 112, 1840. 

 =^Acanthosoraa, De Kay, New York Fauna, Fish., p. 330, ? 1842. 

 Mohe juv., Steenstrup tf Liltken. 

 Orthagorisci juv., Gilnther. 



Dr. Giinther has mistaken for the young of the common Mola rotunda 

 (called by him Orthagoriscus mola) the remarkable genus Molacantkus, 

 and in 1870 quite gratuitously remarked that "these [supposititious] 

 young fishes form a distinct family, Molacanthida', in Mr. Gill's system." 

 Mr. Giinther erred in two respects : (1) in the entirely baseless assump- 

 tion that Molacanthus is the youug of Mola ; and (2) in the statement 

 that Molacanthus had been elevated to family rank " in Mr. Gill's sys- 

 tem." 



Molacanthus is diametrically opposite to the young of Mola,SiS has been 

 well shown by Mr. F. W. Putnam,* and the young of this family, instead 

 of being shorter than the old, are, as might have been anticipated, a 

 priori, from a knowledge of the morphology and relations of the forms, 

 at least as long as, if not longer than, the adult.t Dr. Giinther seems 

 to have bad the material at his command for a proper comi)rehension 

 of the changes of Mola, as he claimed specimens for the British Museum 

 from "1 inch long" to "7 feet long."| If his specimens "1 inch 

 long " really were Molcc, § a simple comparison of them with figures of 

 Molacanthi (if he had no specimens) might have served to convince him 

 of the diiference between the two. If the specimens were Molacanthi, 



* On the Young of Orthagoriscus mola. By F. W. Putnam. [August, 1870.] <[Am. 

 Nat., V. 4, pp. 629-633, Dec, 1870 ; also <Proc. Am. Assoc. Adv. Sci., v. 19, pp. 235-260, 

 1871. 



tl have examined three specimens of Mola rotunda little larger than Molacanthus 

 aculeatus. 



I There was, however, a considerable gaji between the smallest specimens ("/," 

 "A;, I, 1 inch long") and the next (," d," -^ g—i, stuffed, 1^ feet long"); the smallest 

 were probably Molacanthi ; the others Molw. 



^ Dr. Giiuther's descriptive remarks indicate that he had examined also representa- 

 tives of the genus Molacanthus. 



