FISHES — PETROMYZONTIDAE — AMMOCOETES CIBARIUS, 383 



AMMOCOETES, Dura. 



Gen. Char. — Mouth sub-terminal, inferior, lootliless, but provided witliin the buccal disk with numerous short mem- 

 branous cirrhi. Upper lip semi-circular or semi-elliptical ; lower lip transverse and nearly straight. Eyes inconspicuous, 

 scarcely perceptible. All the gills situated within a simple cavity of the chest Two distinct dorsal fins ; second one united 

 to the upper lobe of the caudal. Anal reduced to a mere ridge, gradually merging into the lower lobe of the caudal. 



Stn. — Ammocodes, Dum. Dissert. Poiss. Cyclost. in Mag. Encycl. 1808 ; &, Ichth. analyt. 1856, 112. — Cuv. R6gn. 

 Anim. II, 1817, 110; 2d ed. II, 1829, 406; &, ed. illustr. Poiss. 383.— Guer. Iconogr. du Efegn. Anim. 

 PI. Ixx, figs. 3 & 4— Storer, Rep. Fish Mass. 1839, 198; &, Synops 1846, 2C6.— Dekay, New Y. 

 Fauna, IV, 1842, 383. 



To this genus belong Ammocoetes branchialis, DuM , from the fresh waters of Europe. Iq 

 the northeastern States we find Ammocoetes bicolor, Lesu., as another representative of this 

 genus; and at the northwest of this continent the species whose description follows. 



AMMOCOETES CIBARIUS, Gr.l. 



Spec. Char. — Body sub-cylindrical, somewhat compressed posteriorly, with its surface annulated. Buccal disk sub-ellip- 

 lical, interiorly papillar. Head and chest together, contained four times and a half in the total length. Anterior dorsal 

 fin lower than the second, and separated from it by a space not quite the half of its length. Anal fin very low. Deep 

 olivaceous brown above ; lighter beneath. 



The only specimen of this species which we have so far examined measures four inches in 

 total length. The body anterior to the first dorsal fin is sub-cylindrical, somewhat deeper than 

 broad, wliilst it is compressed posteriorly, and the more and more so as it approaches the tip of 

 the tail, which is acute. The surface of the body exhibits numerous, hence closely approxi- 

 mated, transverse or annular segments, wliich make the general resemblance to a leach most 

 striking. The head is sub-conical, as thick as the body, and rounded off anteriorly. The 

 buccal disk is small, sub-elliptical, the lower rim describing an open curve instead of being 

 perfectly straight. The inner surface of the funnel is provided with jjroportionally large and 

 closely set papillae. The cephalic region, measured from the apex of the snout to the first res- 

 piratory aperture, constitutes about the tenth of the entire length. The seven respiratory aper- 

 tures, which are somewhat vertical, occupy a space longer than the head ; the interval between 

 one another is equal to the diameter of the inconspicuous orbit, which enters four times and a 

 half in the length of the side of the head. 



The anterior dorsal fin is lower than the second, resen.bling in its outline a depressed curve. 

 Its origin is equidistant between the apex of the snout and the tip of the caudal fin; its base 

 entering nearly eight and a fourth of a time in the total length. The intervening space 

 between it and the second dorsal is somewhat less than the half of its length. The vent is 

 situated at one and a fifth of an inch from the extremity of the tail, and somewhat jjosteriorly 

 to the origin of the second dorsal fin, the anterior third of which is more elevated than the 

 rest, and forms an open curve with its upper edge, similar to that of the first dorsal. It 

 diminishes gradually to the upper lobe of the caudal ; the latter again rising, then diminishing 

 towards the tip where the lower lobe of the caudal likewise converges in a like manner. 



The anal fin commences close to the vent under the form of a mere inconspicuous and 

 thickened ridge less than half an inch in extent, with a groove on either side ; both upper and 

 lower lobe of the caudal are somewhat higlier and deeper near the apex of the tail, giving tlie 

 latter a spear-shaped appearance. 



The color is dark olivaceous brown above, the inferior region, from the chest to the vent being 



