354 Bulletiti 47, United States National Museum. 



minute head and very small mouth, found in the waters of Europe, and 

 known as LejHocephalus morrissi. This has been shown by Gill, Giinther, 

 and Facciolii to be the young and larval form of Leptocephalus conger. 

 A number of the genera and species of the supposed family of Lepto- 

 cephalida' have been described, but there is no doubt that all of them are 

 larvto, some of eels, as Contjcr, CoiKjermura'na, OpMsurus, and Xettastoma, 

 others of Isospondylous fishes, as Alhula, EIops, Ahpoccphalus, Siomias, 

 etc. (See Giinther, Cat., viii, 130.) It is thought by Dr. Giinther that the 

 Leptocephalid forms are probably " individuals arrested in the develop- 

 ment at a very early period of their life, yet continuing to grow to a cer- 

 tain size, without corresponding development of their internal organs, 

 and perishing without having attained the characters of the perfect 

 animal." The recent obsers ations of Dr. Gilbert on the larvae of Alhula, 

 Flops, and Conger, however, seem to point to the conclusion that these 

 curious forms are normal young, and that the individuals grow smaller 

 in size for a time with increased age, owing to the increasing compact- 

 ness of the tissues. 



Inasmuch as the name Leptocephalus has been associated for more than 

 a century with larval forms it is a decided inconvenience to accord to it 

 precedence as a generic name over Conger. The strict law of priority, 

 however, demands its retention, and the tendency among systematic 

 zoologists is to recognize as few exceptions as may be to this rule. The 

 unfamiliar names Oxyurus and Uelmictis are both earlier than Conger. 

 {TiETTTuc, slender; K6(t>a/J/, head.) 



a. Dorsal bcgiuuing ucarly oppoeite tip of pectoral ; head about 1| iu trunk. conger, 580. 



aa. Dorsal fin beginning above middle of pectorals ; head about IJ in trunk. 



CAUDILIMBATIS, 581. 



580. LEPTOCEPHALUS COXGER (Llnuaus). 



(CoNOF.R Eel.) 



Dorsal beginning opposite to or just behind tip of pectoral ; eye 1^ in 

 snout, 5 to 6 in head ; snout 3i to 4J in head ; gape extending nearly or 

 quite to posterior margin of eye ; head l.i to IS in trunk ; tail longer than 

 rest of body ; pectorals 3+ in head ; ujiper lip full, with conspicuous pores. 

 Ashy gray or blackish ; vertical fins with a black margin ; body some- 

 times (var. niger) entirely black. Atlantic Ocean, generally common on 

 both coasts, from Cape Cod to Brazil ; also on coasts of Asia and Africa ; 

 almost cosmopolitan, but not found in the eastern Pacific. It reaches a 

 length of 8 feet, and is a food fish of importance, especially in Europe. 

 {Conger, the ancient name of the eel.) 



(i<) Larval Forms. 



Leploccphahis vwriissi, Gmelin, Syst. Nat., 1150, 1788, Holyhead, England. 

 Ophidium pelbuidum, Couch, Loud. Mag. Nat. Hist., v., 1832, 313, 742, England. 

 Leptocephalus graiilis, Storer, Mem. Ainer. Acad., ii, 524, 1839, Massachusetts. 

 LeptocepliaUiK spallanzanii , camUdissimus, etc., of European writers. .. 



(h) Adult Forms. 



Munma supremo numjine pinna: dorstdis niijro, Artedi, Synon., 40, 2, 1738, Mediterranean. 

 Murwna conijur, LlNN.iiUS, Syst. Nat., x, 245, 1758, (based on Artedi). 



