Fishes of the Western North Atlantic 109 



and outer articulation; the two elements of each labial cartilage flexibly joined. The 

 presence of these cartilages, combined with the firmness with which the two jaws are 

 articulated, limits the gape of the mouth. ^'^ Rostral cartilage single but bifid at tip; 

 trough- or shovel-shaped, with a deeper or shallower median depression bounded on 

 either side by a more or less sharply defined ridge; rigid next to cranium but soft and 

 flexible toward its tip; its proximal portion with or without a transverse foramen; 

 anterior margins of antorbital cartilages more or less dissected, with or without one 

 or two isolated cartilages on either side between each of them and rostral cartilage. "=* 

 Each electric organ with an average of 146—428 columns in the species in which they 

 have been counted."* Characters otherwise those of the family. 



Sixe. The maximum length definitely reported for Narcine appears to be about 

 30 inches (762 mm),"^ the second longest 18 inches,^i^ sizes far below the length 

 reached by species of the genus Torpedo (p. 85). 



Developmental Stages. The inner walls of the uterus are thickly set with villi (up 

 to 200 per sq. in. of uterine surface), as is generally the case in ovovlviparous batoids. 

 These villi are spatulate in form and are provided with a dense net of capillaries. Ap- 

 parently they secrete the yellowish milky solution that fills the uterus and probably 

 nourishes the embryo. In embryos at a stage when the external gill filaments still per- 

 sist, the anterior limits of the pectorals may still be marked by deep notches in the 

 margins of the disc, or the notches may have disappeared already."' In either case, 

 the pectoral notches have disappeared before birth in all species of the genus, so far 

 as is known. 



Habits. The various species of Narcine are most commonly encountered close to 

 land, in water so shoal that they can be taken in seines hauled from shore, or they can 

 be seen lying on bottom. And 60 fathoms appears to be the maximum depth recorded 

 for the genus. They have been described as sluggish in habit. The fact that the pro- 

 tractile mouth cannot be gaped widely would suggest that they subsist on less active 

 and smaller prey than members of the genus Torpedo (p. 102). In fact, the stomach 

 contents of the few specimens examined have consisted solely of polychaete worms, 



112. These cartilages with their attached muscles were described and accurately pictured for Narcine brasilietisis more 

 than a century ago by Henle (Ueber Narcine, 1834: 12, pi. 4, fig. 2); they have been illustrated more recently for 

 Narke japonica by Garman (Mem. Harv. Mus. comp. Zool., 36, 1913: pi. 67, fig. 3). 



113. For a general account of the head skeleton with illustrations, see Holmgren (Acta Zool. Stockh., 22, 1941 : 57-59, 

 figs. 50-55)- 



114. The number of columns in the Indo-Pacific species [Narcine tasmaniensis, N. lingula, N.timlei, and N.indica) 

 average from 146-27S per organ, those in adult .V. brasiliensis (Fritsch, Elektr. Fische, 2, 1890: 98; Cox and Breder, 

 Zoologica N. Y., 2S, 1943: 46) from as few as 380 to as many as 428. 



115. Breder (Bull. Bingham oceanogr. Coll., 2 (i), 1928: 5) for a specimen of Narcine entemedor; jaws only. 



116. Reported for N. brasiliensis (p. 118); also for N. tasmaniensis by Whitley (Fish. Aust., j, 1940: 164). A two-foot 

 specimen from the west coast of Mexico, reported by Kumada and Hyama (Marine Fish Pac. Coast Mexico, 1937: 

 21) as a Narcine, may not have belonged to that genus, for they describe its snout as "much angular." 



117. See Prashad (Rec. Indian Mus., ig, 1920: 104, pi. 7, figs. 4-9) for an account of the uterine wall in Narcine indica 

 Henle 1834 and for illustrations of embryos with the anterior parts of the pectorals still separate from the sides of 

 the head. For illustrations of an embryo of N. limlei (which we have examined) at about the same stage in devel- 

 opment but with the pectorals fully united with the sides of the head, see Garman (Mem. Harv. Mus. comp. Zool., 

 36, 1913; pi. 61, fig. 6). 



