42 
BULLETIN OF THE BUREAU OF FISHERIES 
/. Snout tubular, bearing a small mouth at the tip; tail long, sometimes pre- 
hensile; body covered with bony rings 
Syngnathidse (pipefishes and seahorses) , p. 181 
ff. Snout not tubular; mouth small, terminal; tail of moderate length; body 
covered with boxlike shell, composed of polygonal plates 
Ostraciidse (trunkfislies) , p. 345 
ee. Body not inclosed in a bony armor; the skin naked, with scales, or beset with 
prickles and spines of varying sizes. 
g. Teeth fused, forming a continuous cutting edge; body not compressed, 
somewhat globular in form and capable of considerable inflation; dorsal 
fin single. 
h. Teeth in each jaw anteriorly divided by a median suture; skin smooth or 
more or less prickly Tetraodontidse (puffers), p. 346 
hh. Teeth in the jaws undivided, having no median suture; body covered 
with strong bony spines Diodontidx (porcupine fishes), p. 349 
gg. Teeth separate, not fused and not forming a continuous cutting edge; body 
rather deep, compressed; two dorsal fins. 
i. First dorsal with three spines; scales rather large, bony, bearing spines 
or bony tubercles Balistidx (trigger fishes), p. 340 
ii. First dorsal consisting of a single spine; scales small, bearing slender 
spines, making the surface of the body rough, velvety 
Monacanthidx (filefishes) , p. 342 
Class LEPTOCARDII 
Order AMPHIOXI 
Family I.BRANCHIOSTOMID/E. The lancelets 
Body elongate, compressed, tapering gradually to both extremities; mouth a longitudinal slit 
surrounded by a fringe of cirri; eyes and fins rudimentary; color pale, translucent. A single genus 
is represented in United States waters. 
1. Genus BRANCHIOSTOMA Costa. Lancelets 
Reproductive organs present on both sides of the median line; anal fin present, with traces of 
rays; vertebral column not produced backward into a caudal process. 
I. Branchiostoma virginise Hubbs. Amphioxus; Lancelet. 
Amphioxus lanceolatus Rica, 1878a, p. 503; Andrews, 1893, p. 238. 
Branchiostoma lanceolatum Jordan and Evermann, 1896-1900, p. 3, PI. I, fig. 1. 
Branchiostoma virginiz Hubbs, Occ. Papers, Mus. Zool., Univ. Mich., J^o. 105, 1922, p. 8; Sewell s Point, Va. 
“ The lancelet of Chesapeake Bay appears to differ from the other American species of the genus 
in the increased number of myotomes. In this respect it resembles the European B. lanceolatum , 
from which, in turn, it is distinguished by the more posterior position of the anus in reference to 
the lower lobe of the caudal, the relatively shorter distance between this fin lobe and the atriopore, 
and the more numerous dorsal-ray chambers. It is more closely related to floridx than to lanceo- 
latum. All of the lancelets from the east coast of the United States, variously referred to lanceolatum 
or caribxum, are perhaps conspecific with the Chesapeake form. It seems not improbable that 
virginise and floridx will be found to intergrade. 
“Dorsal-ray chambers, 259 to 309 (average of five, 279); anal-ray chambers, 36 to 40 (average 
of six, 38). Dorsal-ray chambers about two or three times as high as long; dorsal fin about one- 
eighth as high as body. Anus near middle of lower caudal lobe; origin of this lobe about midway 
between tip of tail and atriopore. Postanal length, 8.5 to 11.5 in total. Preatrioporal length, 2.4 
to 2.7 times postatrioporal length. Myotome formula: 36 to 40+14 to 16 + 9 to 12 = 60 to 64 
(in type material) ; 36 to 38+13 or 14+11 to 15 = 61 to 64 (according to Andrews, 1893). Maximum 
length, 5.3 cm. (Andrews, 1893.) ” (Hubbs, 1922.) 
