Jordan and Evcrmann. Fishes of North America. 1753 



686. MOLA, Cuvier. 



(HEAD-FISHES.) 



Mola, CUVIER, Tableau leni. Hist. Xat. Auimaux, 323, 1798 (rotunda. viola). 

 Orthragoriscus, BLOCK, Syst. Ichth., Schneider Ed., 510, 1801 (mold) ; misprint for Orthago- 



riscui. 



Cephalus, SHAW, General Zoology, v, 2, 432, 1804 (mola). 

 Orthragus, RAFINESQUE, Caratt. Ale. Nuov. Gen. e ISTuov. Sp. Anim. e Piante della Sicilia, 17, 



181Q (luna mola). 

 Diplanchias, RAFINESQUE, Caratt. Ale. Nuov. Gen. e Nuov. Sp. Anim. e Piante della Sicilia, 



17, 1810 (nasus = mola). 

 Tympanomium, RANZANI, Novi Comm. Ac. Sci. Bonon., v, 3, pi. after p. 81, 1837 (planci= 



mola). 

 Trematopsis, RANZANI, Novi Comm. Ac. Sci. Bonon. ,v, 3, pi. after p. 81, 1837 (willughbeii= 



mola). 



Ozodura, KANZANI, Novi Comm. Ac. Sci. Bonon., v, 3, pi. after p. 81, 1837 (orsini = mola). 

 Pedalion (GUILDINO MS.) SWAINSON, Nat. Hist, and Class'n Fishes, etc., v, 1, 199; v,2, 195, 



329, 1839. 

 Aledon, CASTELNAU, M6m. sur Poissons Afrique Aust., 75, ?1860 (storeri = mola). 



LARVAL FORMS. 



Molacanthus, SWAINSON, Nat. Hist, and Class'n Fishes, etc., v, 2, 195, 329, 1839 (pallasi). 

 Pallasia, NARDO, Ann. Sci. Regno Lombard., Venet., v, 10, 112, 1840 (pallasi). 

 Acanthosoma, DE<KAY, New York Fauna: Fishes, 330, 1842 (carinatum). 

 Centaurus, KAUP, Archiv. Naturgesch. 1855, 1, 221 (loops). 



Body ovate, strongly compressed, covered with a thick, rough, leathery, 

 elastic skin, which is without bony plates. Profile forming a projecting 

 ileshy nose above the mouth. Dorsal fin beginning not far behind pecto- 

 rals, short and high, falcate, confluent with the anal around the tail; no 

 large spines on the body. Clumsy fishes, found in most warm seas, reach- 

 ing a great si/e ; the young (Molacdntlim} * with the body deeper, much com- 

 pressed, without trace of caudal fin, its place taken by a row of marginal 

 spines, (mola, a millstone.) 



2172, MOLA MOLA (Linnajus). 



(SUNFISH; HEAD-FISH; MOLA; PEZ LUNA.) 



Head 3; depth T*. D. 17; A. 16. Dorsal and anal fins high in front, 

 rapidly decreasing backward, the height of each about 2 in length of 

 body in adult; caudal fin low, with a wavy outline. Depth always more 



The nominal genus Molacanthus, Swainson (Pallasia, Nardo; Acanthosoma, De Kay) 

 lias thus been denned: Body suhorbicular, much compressed, deeper than long, covered 

 by a thin silvery skin on which are many strong spines. Dorsal and anal fins high and 

 short, not confluent, the space on the tail between them occupied by a row of small spines ; 

 no interspinal bones for the support of the caudal : pectorals moderate. Intestines short, 

 with but 2 turns. These small fishes were long generally considered as the young of 

 Mola. The researches of Prof. Frederick Ward Putnam (Am. Nat., Dec., 1870) seemed to 

 show that they were adult fishes allied to Mola, careful comparisons having been made by 

 him between Molacanthus and the young of Mola. In a specially valuable paper ' ' On the 

 origin of heterocercy and the evolution of the fins and fin rays of fishes " (Kept. U. S. Fish 

 Comm. for 1884), the late Prof. John A. Ryder, of the University of Pennsylvania, has 

 carefully discussed the relations of Molacanthus to Mola. The researches of Professor 

 Ryder leave no doubt that Molacanthus is simply a post-larval phase in the development 

 of Mola, as was supposed by Liitken, Steenstrup', and Giintber. According to Kyder, the 

 earliest forms of Mola (corresponding to the form called Ostracion boops by Richardson) 

 will be found to have a distinct tail. 

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