FISHES FROM NORTHEASTERN PACIFIC— CHAPMAN 516 



maxillary (absent in Opisthoprodus) , which is broadly expanded 

 posteriorly; by the perfectly normal anal fin, which is larger than the 

 dorsal, and the normally placed anus (in Opisthoprodus the anus 

 opens posteriorly near the base of the caudal fin; the anal fin is nor- 

 mally atrophied and is either very small and only slightly separated 

 from the caudal, or is so closely appressed to the latter that it appears 

 to be absent) ; by the differences in the size and shape of the opercle 

 and subopercle {Opisthoprodus has the opercle long and narrow; the 

 subopercle is very small and is almost hidden by the preopercle) ; by 

 the lack of a ventral sole (this peculiar structure, characteristic of 

 Opisthoprodus, consists of a flattened ventral surface which projects 

 more or less beyond the normal outline under the head and is sup- 

 ported by the anterior arms of the cleithra); by the position and 

 extreme length of the ventral and pectoral fins (in Opisthoprodus the 

 ventral fins project into the ventral outline and are of normal length) ; 

 and by numerous other peculiarities (see Trewavas, 1933). The new 

 genus and species resembles Opisthoprodus in the small gape, the 

 general shape of the body, the presence of an adipose fin, and the 

 dorsally directed eyes. 



Named in reference to the elongate pectoral and ventral fins and 

 the tiny mouth. 



Family MELANOSTOMIATIDAE 



PHOTONECTOPS, new genus 



Genotype. — Photonedops multipundata, new species. 



Stomiatoid fishes having the general characters of the Melano- 

 stomiatidae as defined by Parr (1927). Vertical fins confined to the 

 tail; dorsal and anal fins beginning at the same vertical and covered 

 with only normal fin membrane. Pectoral fins absent. Pelvic fins 

 close together and inserted well behind the middle of the body. 

 Vertebrae 82 as counted by Dr. Schultz and Mr. Reid of the National 

 Museum from an X-ray of the type made through the courtesy of offi- 

 cials of the U. S. Naval Hospital. 



Mouth noticeably curved upward so that the symphysis of the 

 lower jaw projects beyond the snout when the mouth is closed. Teeth 

 in lower jaw very numerous with some fanglike; arranged in many 

 oblique rows. Teeth on maxillary also arranged in several rows. Pre- 

 maxillary teeth stout and recurved, not depressible. Two rows of 

 large depressible fangs on the "tongue." Teeth present on the 

 palatines but not on the vomer. 



Snout rather reduced; not protractile or movable. Normal 

 membranous floor between lower jaws. Lateral photophores well 

 developed and very numerous. A large suborbital organ posteriorly; 

 a smaller an tero ventral luminescent organ on the border of the eye; 

 and a similar small organ on the anterodorsal margin of the eye. 



