PHYSOCLISTI. 
367 
593. N. avocetfa Jordan & Gilbert. 
Head slenderer, its depth one-ninth its greatest length. Eye large, 
one-third the head, without snout. Length of pectoral scarcely greater 
than height of anal, which is scarcely less than the greatest depth of 
the body, and more than the greatest depth of the head. Translucent; 
belly with close-set dark spots, its lower edge and anal fin black, the 
back abruptly white and unspotted. L. 22 inches. Head 10; depth 58; 
depth of anal 61 in length of body. Puget’s Sound; one example 
known, differing in some slight respects from all Atlantic specimens 
examined. 
(Jordan & Gilbert, Proc. U. S. Nat. Mus. 1880, 409.) 
Sub-class PHYSOCLISTI. 
(T//e Physoclistoiis Fishes.) 
Air-bladder, if present, without pneumatic duct, in the adult. Parietal 
bones separated by the supraoccipital. Ventral fins usually thoracic or 
jugular, normally with 1 spine and 5 soft rays. Pectoral fin normally 
inserted high, with vertical base. Vertical fins usually with spines. 
Premaxillaries normall}' forming the entire border of the ui>iYer jaw. 
Tail homocercal. bladder; xAsjVro?, closed.) 
ANALYSIS OF THE ORDER OF PHYSOCLl!-^. 
a. Scapula suspended to the anterior vertebrie ; maxillary distinct ; superior bran- 
cbihyals and pbaryngeals present ; inferior pharyngeals not united; no 
interclavicles; body elongate ; ventral fins abdominal or wanting. 
. Opisthomi, P. 
aa. Scapula suspended to the cranium by a post-temporal. 
i. Lower jibaryugeals co-ossified ; fins without sjiines ; ventral fins abdominal; 
third and fourth superior pharyngeals much enlarged. 
Synentognathi, Q. 
Ih. Lower pharyngeals separate (or if united, fins with spines and ventrals thoracic), 
c. Gills tufted ; superior branchihyals and pharyngeals and basal branchihyals 
wanting; ventrals, if present, abdominal Lopiiobranchii, R. 
cc. Gills pectinate. 
d. Superior branchihyals and pharyngeals reduced in number ; ventrals abdom- 
inal Hemibranchii, S. 
dd. Superior branchihyals and pharyngeals normally developed; ventrals mostly 
thoracic or jugular. 
e. Bone.s of the jaws not united. 
/. Pectoral fins not pediculate, the gill-openings in front of them. 
g. Cranium normal Acanthopteri, T. 
gg. Cranium anteriorly twisted; both eyes on the same side of the head. 
Heterosomata, U. 
ff. Pectoral fins pediculate, their basal bones reduced in number and elon- 
gate; gill-openings in the axils Pediculati, Y. 
ee. Bones of the jaws co-ossified ; the dentary with the articular, and the pre- 
maxillaries with the maxillaries Plectognathi, W. 
