188 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL.9 



anterior end of upper lip. Posterior nostrils an elongate pore without a 

 raised rim, placed before eye at its mid-depth. A well-developed pore 

 above posterior nostril. Two enlarged pores between anterior nostrils. 

 A large pore placed immediately behind the base of the anterior nostril, 

 its edge expanded into two leaflike flaps, which fold one over the other to 

 partially close the opening. 



Premaxillaiy, vomerine, and maxillary teeth closely united at front of 

 upper jaw. No interspaces between the tooth bands. Premaxillary teeth 

 almost entirely outside the mouth when it is tightly closed and seen from 

 directly below. Maxillary teeth anteriorly in narrow bands of close-set, 

 pointed teeth ; tapering laterally to several irregular rows. Mandibular 

 teeth similar to maxillary teeth. Vomerine teeth closely set and pointed 

 anteriorly, becoming more widely spaced and conical posteriorly. A few 

 anterior premaxillary teeth slightly enlarged. Upper lip with a narrow, 

 upturned, labial flange. Labial canal present, no bony processes extend- 

 ing downward into the oral edge of the lip. Inferior edge of labial canal 

 unmodified. 



The above description was made from a 445 mm specimen (paratype) 

 oi Alloconger flavirostris (Stanford 21100) from Misaki, Sagami, Japan 

 and in the collections of the Natural History Museum, Stanford 

 University. Although Parr (1932, p. 27) placed Alloconger in provi- 

 sional synonymy with Ariosoma, it may be easily distinguished from that 

 genus by the absence of the two or three pointed, bony processes that 

 extend downward into the edge of the upper lip. 



THYREOGONGER, new genus 



Genotype. — Thyreoconger hemiaspidus, new species 

 Body elongate, slender; dorsal and ventral outlines extending back- 

 ward almost parallel to one another to posterior third of tail, thence 

 gradually tapering to a moderately rounded caudal tip. Body sub- 

 cylindrical anteriorly, becoming compressed posteriorly on tail. Tail 

 slightly longer than head and trunk. Dorsal origin over pectoral base, 

 confluent with anal around tip of tail. Pectoral fins well developed; 

 ventral fins absent. Snout moderate, bluntly pointed, extending slightly 

 beyond premaxillary teeth. Anterior nostrils tubular, directed down- 

 ward on edge of upper lip, close to tip of snout. Posterior nostrils large, 

 with thickened and slightly raised rims, placed before eye at its mid-depth. 

 Pores on head large and numerous. 



