624 PROCEEDINGS OF THE NATIONAL MUSEUM. vol. xxv. 



ganoid plate (" interclavicle'') of hj'^pocoracoid more or less devel- 

 oped; postclavicle absent; actinosts small, without open spaces 

 between; anterior vertebrae scarcely enlarged, not ankylosed; ventrals 

 placed anteriorly; spinas dorsal represented by isolated spines; hyper- 

 coracoid foramen partly bordered by clavicle anteriorly; ribs devel- 

 oped. 



a. Branchiostigals o; ventrals with one soft ray each; snout conic, or but slightly 

 tubiform; post-temporal and supraclavicle present; typical ribs present. 



Gasterosteklse. 



aa. Branchiostigals 4; ventrals with 4 soft rays each; snout tubiform; clavicle 



attached to cranium by one of the lateral line series of bones; ribs (or 



epipleurals) terminating in lateral plates Aulor-hynchidss. 



AULOSTOMOIDEA. 



Parietals absent; pterotic interposed between and entirely sepa- 

 rating prootic from exoccipital; condyle of basioccipital a round knob 

 forming a ball-and-socket joint with atlas; basisphenoid bridging ante- 

 rior edges of prootics above rectus muscles of eye making basis cranii 

 appear Rouble, but no myodome is in continuation; a long splint-like 

 shield of bone is on each side of back attached in sockets of epiotics; 

 hypocoracoid with a backward extending process (*'interclavicle"); 

 postclavicle present, smiple; lower 3 actinosts subequal rod-like, with 

 large open spaces between them; anterior 4 vertebra? elongate, anky- 

 losed, and with coinciding bon}' dorsal bucklers above; ribs absent; 

 ventrals placed at about middle of belly. 



a. Skin smooth; body depressed; no dorsal spines developed; post-temporal suturally 

 united to cranium; palatines normal, free from cranium; transverse processes 



normal Fistulariidse. 



aa. Skin with well-developed ctenoid scales; body compressed; spinous dorsal devel- 

 oped; post-temporal not united to cranium; palatines united to each other and 

 to cranium; each transverse process behind fourth vertebra is formed equally 

 by a process from each adjoining vertebra (or each end of each vertebra carries 

 a half of each transverse process Aulostomidse. 



MACRORHAJtPHOSOIDEA. 



Parietals absent; pterotic normal in position; condyle of basiocci- 

 pital concave; myodome present, well developed; basisphenoid small; 

 no process or ganoid part (interclavicle) present on hypocoracoid; 

 postclavicle present; actinosts without a space between them, the low- 

 est elongated cutting into the hypocoracoid; post-temporal suturally 

 united to cranium; supraclavicle coosified with clavicle; hypercoracoid 

 entirely surrounding its foramen; anterior vertebra somewhat 

 enlarged, not united; transverse processes not united to form a lateral 

 shelf; ribs absent; spinous dorsal well developed; ventrals placed at 

 middle of abdomen. 



Characters of the family included above Macrorhamphosidas. 



