126 
BUI.I.ETIN OF THE BUREAU OF FISHERIES. 
the material before me I am not able to make any satisfactory table for their separation. Leucichthys 
nigripinnis is distinct by the evident laterobasal angles. Coregonm coulteri scales are about 1.5 mm, 
long by 2 broad, varying to approximately circular, but apparently never (at least on the middle of the 
side of the fish) longer than broad, as is usual in the Salmo group. The circuli are very widely spaced, 
and there are rather obscure indications of laterobasal angles. These Coregonus scales are perhaps 
immature. It is probable that the following characters are valid for the subfamilies: 
CoREGONiNiE, Whitefishes AND Lake Herring. — Scales as broad or broader than long, with 
laterobasal angles more or less developed. 
Salmonin^, SALMON, TROUT, ETC. — Scales nearly always longer than broad, without laterobasal 
angles. Of these, the Coregoninas must apparently be considered the more primitive. 
ARGENTINID^E. Smelts. 
Osmerus mordax Mitchill, from Menemsha Bight, Mass. (J. T. Field), has approximately circular 
scales about 2.5 mm. diameter, without radii. The circuli are very widely spaced except basally, where 
they are crowded ; they are obtusely angled in the middle line above and on each side. The laterobasal 
comers are very obtuse but evident; the basal middle is broadly produced into a roimded lobe, which is 
usually emarginate. The nucleus is far toward the base of the scale, approximately on a level with the 
laterobasal comers. 
This scale is in general related to that of the Coregoninse, but is readily distinguished by the position 
of the nucleus. 
SYNODONTID/E. Lizard-fishes. 
Rather large semicircular cycloid scales; nucleus a little (Trachinocephalm) or considerably (Syno- 
dus) above the middle; very strong basal plicae (2 or 3 in Trachinocephalus, 3 or 4 in Synodus)] circuli 
normal, quite dense in Synodtis, rather widely spaced in Trachinocephalus , the apical ones longitudinal; 
laterobasal angles evident but obtuse ; apical marginal area broadly thin and sculptmeless, in the manner 
of certain clupeids, but the submarginal area, or marginal area of the scale proper, sculptureless, except 
for scattered pimctiform markings, its margin irregularly minutely dentate (more evidently in the 
Synodus), as if very irregularly broken. Scales of Synodus yellowish, of Trachinocephalus colorless. 
The species studied are Trachinocephalus myops (Fonster), the groxmd spearing, from Woods Hole, 
Mass., and Synodus foetens Linnseus, the lizard fish (pi. xxxv, fig. 19), from Galveston, Tex. (Evermann). 
The apical stmcture seems to be prophetic of the acanthopterygian type of ctenoid scale ; in the Gerridae 
{Xystcona cinereum Walbaum) the apical margin is very thin, covered with minute shadowy diamond- 
shaped markings, the vestiges of the disappearing teeth ; no such vestiges can be seen in the Synodontidae, 
although the superficial appearance is similar. Jordan notes of Synodontidae that the head is scaly, 
“a character rare among the soft rayed fishes,” but usual among Acanthopterygians. 
MAUROLIClDiE. 
Maurolicus pennanti (Walbaum), from Woods Hole, Mass., has easily deciduous, extremely thin 
scales, witli widely spaced evanescent circuli. According to Jordan, tlie Maurolicidse are scaleless, but 
no doubt the specimens examined had lost their scales. Dr. F. B. Sumner tells me that he carefully 
worked over the Woods Hole species and noted the presence of scales. 
In the related family of Myctophidse, the lantern fishes, the scales of Myctophum resplendens , as 
figured by Gunther, are better developed; broad, cycloid, regularly circulate, nucleus nearly central, 
about six strong basal folds. They are rather like those of Cypsilurus . 
Order APODES. Apodal fishes. 
Suborder Enchelycephaui. The eels. 
ANGUILLIDAJ. Fresh-water eels. 
The scale of the common eel {Anguilla rostrata or chrisypa) is a remarkable structure, very unlike 
any of the scales discussed above. It is 2 mm. long, or slightly over, narrow, and with rounded ends, 
approximately sausage-shaped in outline. The nucleus is central, and on an extremely fine reticulated 
