24 CALIFORNIA ACADEMY OP SCIEKCES 



34. Galeichthys xenauchen {Gilbert). 



Plate IV, Fig. 8. 



Hexancmatichthys xenauchen Gilbert (Jordan & Evermann 1898, p. 2777). 



In apjjearance, 6-'. xennnclien is most closely allied to species of Netuma, 

 having the low depressed head, with the lateral outlines converging forwards to the 

 narrow pointed snout, and a long largely adherent adipose dorsal. The palatine 

 patches are, however, narrow, and without backwardly projecting lobes. The species 

 is distinguished from all those known from the Pacific Coast of America by the long 

 and extraordinarily narrow occipital process. 



Type, a female 38 cm. long. 



Head 3^ in length; depth at front of dorsal 5!; anal with 23 rays. Width of head at opercle 

 iij- in its length; width at front of eyes 2 in head. Width of mouth at inner angles 2| in head. 

 Interorbital width 2 j'j. Eye very small, 9 in head, 3I in its distance from tip to snout, 4I in postocular 

 part of head, 4^ in interorbital width. 



Teeth all villiform. Mandibular bands well separated on middle line, very broad mesially, 

 rapidly tapering to a point laterally, the band produced beyond angle of mouth, its greatest width 

 contained 2| times in its length. Premaxillary band very conve.xly curved, following the outline of the 

 snout, its width 5I in its length. Vomerine patches roundish, separated by an evident medial groove, 

 marked off from the palatine patches by a narrower groove and a constriction. The palatine patches 

 are equal in width to the vomerine patches, and less than twice as long. They are of nearly equal 

 width throughout. 



Maxillary barbels very slender, reaching slightly beyond the base of the pectoral spine. The 

 mental barbels do not reach edge of gill-membrane, the outer pair equaling length of snout and half of 

 eye. Nostrils very large, the anterior broadly oval, with widely reflexed rim, the posterior widely 

 elliptical, not concealed by the valve. Distance from anterior nostril to tip of snout equaling that from 

 posterior nostril to front of eye. 



Fontanel wide, with nearly parallel edges on frontal region, abruptly narrowing at front of 

 occiput, where it is continuous with a narrow and shallow groove. The latter fails to reach base of 

 occipital process by a distance equaling half diameter of eye. The raised margins of the fontanel are 

 continuous with a pair of sharp ridges bounding the groove, these accompanied by a pair of 

 lower ridges on their outer sides and parallel with them. Posteriorly, these ridges are roughened with 

 granules, and merge into the granulated area on posterior part of occiput. Occipital process granu- 

 lated, the granules arranged in more or less definite lines radiating backwards and downwards on each 

 side from median point of base. Lateral portions of occiput with an area of radiating striae, separated 

 from the central ridges by a smooth groove-like depression. A narrow granulated area extends 

 forward on each side of fontanel to above back of orbits. The occipital process is very long and 

 narrow, its width opposite its middle being but f of its length. Near base it abruptly expands, the 

 basal width being half its length plus that of dorsal plate on median line. Opercles and humeral 

 plate weakly striate. Gill-membranes with a wide free fold posteriorly. Gill-rakers weak and short, 

 I -f 4 movable ones. No evident axial pore. 



Dorsal spine slender, with a series of .sharp granulations on anterior edge; minutely roughened, 

 not serrate behind. It is broken in the type, but its length was about f that of head. Pectoral 

 spines rather slender, rough granular on outer margins, with short fine serrje within. Both are 

 mutilated in the type, but their length was about equal to that of dorsal spine. The pectorals 

 extend nearly | distance to ventrals, the ventrals nearly to origin of anal. Distance from anus to 



