234 
BULLETIN OF THE UNITED STATES FISH COMMISSION. 
the illustrations of the heads of the adults. The photogravures of A. brevirostris also 
show the great difference in the dermal armature of that species in comparison with 
that of the young of the common species. In the former the strong spines of the i 
bucklers have disappeared, while in the latter of the same age they are still retained. . 
2. SYSTEMATIC REVIEW OF THE STURGEONS OF THE EASTERN COAST. 
The following systematic review of the sturgeons of the Eastern coast is here 
offered. The defluitions of the order, family, genus, and the two Eastern species are 
modified and corrected so as to correspond with the present state of our knowledge 
of tbe group. This has been found necessary, since a few minor errors as to matters 
of fact have crept into the definitions given in Jordan and Gilbert’s “ Synopsis of the 
Fishes of North America,” upon which the ones here given are based. 
Order GL^NIOSTOMI. 1 
> ■ 
A prsecoracoid arch ; symplectic represented by cartilage, but without membranous V 
ossification; maxillary present; no suboperculum or prseoperculum; interoperculum j 
present; mesopterygium distinct; interclavicles present; basihyals and ceratohyals 
without membranous ossifications; branchihyals partially invested by ossifications in 
membrane. 
Family ACIPFNSERID^. i- 
1 ' 
The Sturgeons. • ' 
Body elongate, subcylindrie ; skin armed with five rows of bony bucklers, each l 
with a median longitudinal carina, terminating in a retrorse spine in the young and in ’’ 
some small species. A median dorsal series, and a lateral and abdominal series on 
each side, some of the abdominal series in later life (the preanals of A. sturio, and 
abdominals of A. rubicundus) becoming covered and more deeply embedded in the i 
integument, so as to become invisible from the surface. The lateral rows of scutes give • j 
passage to the canal of the lateral line. Between the rows of large scutes the skin is ) 
rough with small, irregular, embedded dermal ossifications. Snout produced, depressed, ' 
conical or subspatulate, with sensory areolae on inferior surface. Mouth small, .'• f 
inferior, protractile, with thickened lips, produced into characteristic marginal lobes. L 
No teeth, except in the larval stages. Four barbels in a transverse series on the lower 1 1 
side of the snout in front of the mouth. Eyes small ; nostrils large, with two open- i I 
ings, and with olfactory membrane with a smooth central disk, surrounded by a 'ji 
rosette of folds. Gills 4; branchial arches 5; an accessory opercular gill. Gill mem- * ■ 
brane united to isthmus. No branchiostegals. Maxillary distinct from premaxillary. 
Head covered by bony scutes or dermal ossifications united by sutures. Fin-rays - 
slender, all articulated, except first spine like ray of pectoral. Caudal with fulcra, 
pectorals placed low. Ventrals rnany-rayed, behind middle of body. Dorsal placed 4 | 
posteriorly; anal somewhat behind it, similar. Tail heterocereal; the lower lobe f 
developed. Air-bladder large, simple, connected with the (BSO[)hagus by a spacious ';l 
laterally compressed, short pneumatic duct. Pseudo- branchial or spiracular gills very * j 
