Jordan and Evermann Fishes of North Amet ica. 2495 



branes somewhat united, free from the isthmus; no pseudobranchife ; no 

 pylorio caeca; vertical fins very low, confluent, without spines; no ven- 

 tral fins ; pectoral fins present or absent. Small shore fishes of tropical 

 seas, often living in shells of mollusks, echinoderms, etc., being especially 

 often commensal with the pearl oyster and with the larger Hololhuria. 

 Genera 3; species 12. (Ophidiida, group Fierasferina, Giinther, Cat iv 

 381-384, 1862.) 



a. Pectoral fins present; no distinct caudal fin; gill membranes connected anteriorly 

 onl y- FIERASFER, 952. 



952. FIERASFER, Cuvier. 



Fierasfer, CUVIER, Regne Anim., Ed. 1, n, 239, 1817 (imberbe=acu). 

 Echiodon, THOMPSON, Proc. Zool. Soc. London 1837, 55 (drummondi). 

 Diaphasia, LOWE, Proc. Zool. Soc. London 1843, 92 (acus). 

 Oxybeles, KICHARDSON, Voy. Erebua and Terror, Fishes, 74, 1844-48 (homei). 

 Porobronchux, KAUP, Ann. Mag. Nat. Hist. 1860, 272 (larva of Fierasfer acus). 

 Carapus, * GILL, Proc. Ac. Nat. Sci. Phila. 1864, 152 {after RAFINESQUE, 1810; not type). 

 Vexillifer, GASCO, Bull. Assoc. Nat. Med. Napoli 1870, 59 (larva of Fierasfer acus). 

 Lefroyia, JONES, Zoologist, IX, 1874,3838 (bermudensis) . 



Gill membranes little connected, leaving the isthmus bare. No distinct 

 caudal fin ; pectoral fins developed. The species of this genus are not well 

 known, and their characters and nomenclatures are uncertain. It is not 

 unlikely that the American species are all reducible to one, Fierasfer affinia 

 or dtibius, but our scanty material will not justify us in taking this view. 

 (Fierasfer, the ancient name, from 0ze/9Of, sleek and shining.) 



a. Vomer with canine teeth; pectoral about length of head. 



6. Front teeth of upper jaw enlarged; head 7 to 8 in length; depth 11 to 15 times 



in length of body. AFFINIS, 2867. 



bb. Front teeth of upper jaw not enlarged; head 6 in length; depth about 10J 



times in length of body. ARENICOLA, 2868. 



aa. Vomer with small teeth, scarcely canine-like; pectoral about 2 in head; head 7 to 



8 in body. BERMUDENSIS, 2869. 



2867. PIEBASFER AFFINIS t (Gunther). 



(PEARL-FISH.) 



Head 7|; depth of head 15. Maxillary extending slightly beyond orbit; 

 lower teeth larger than the upper, except 2 to 4 front teeth of upper jaw, 

 which are about equal to lower teeth; vomer with 3 to 6 teeth, 2 or 3 of 



* The name Carapus, Rafinesque, has been substituted for Fierasfer by Gill and Poey. 

 This change seems to us not justifiable, as it is certainly not desirable. The name Cara- 

 pus first appears in Rafinesque's Indice d'lltiologia Siciliana, 57, 1810. No type is men- 

 tioned by Rafinesque, but the diagnosis is taken from that of Lacepede's second subgenus 

 under Gymnotus, which contains the three species, carapo, fierasfer, and longirostratu*. 

 Of these species, carapo is the original Linnaean type (Ed. x) of the genus Oymnotus. 

 Carapus should therefore be regarded as a synonym of Gymnotus. The Brazilian name 

 carapo evidently suggested the word Carapus, although Dr. Gill derives the name from 

 Kapa, head; arrow?, footless, an ex post facto distinction from Ophedion. In a list of Sicil- 

 ian fishes, on page 37 of Rafinesque's Indice, published somewhat later, the name Cara- 

 pus acus appears for Fierasfer acus. This reference of a species of Fierasfer to Gymnotus 

 or Carapus was due to Rafinesqne's ignorance of its relations. 



t In the Museum of Comparative Zoology is "one valve of a pearl oyster, in which a 

 specimen of Fierasfer dubius is beautifully inclosed in a pearly covering, deposited on it 

 by the oyster." (Putnam.) 



