350 



PROCEEDINGS OF THE NATIONAL MUSEUM. 



vol. 48. 



Known only from the type and a single paratype from the same 



station. 



X. latifrons. X. leiops. 



1. No black blotches on sides. 



2. Black margin of spinous dorsal of uni- 



form width. 



3. 14 to 16 plates in median series behind 



dorsals. 



4. A series of 4 to 6 strong spinelets on 



eyeball. 



5. 3 to 5 pairs of well-developed postanal 



plates. 



6. Plates on breast stronger, usually in 



contact, completely covering the 

 area. 



7. Pectoral nearly truncate, the thicken- 



ed lower rays 5 in number, the long- 

 est of these little produced beyond 

 general margin of fin. 



8. Vertical fins more posteriorly inserted, 



the length anterior to the spinous 

 dorsal one-third the total to base of 

 caudal. 



9. Caudal posteriorly rounded. 



A series of oblong black blotches on 

 sides. 



Black margin of dorsal widened an- 

 teriorly to include greaer part of first 

 interspinous membrane. 



18 or 19 plates behind dorsals. 



No spinelets on eye. 



Median pairs of postanal plates little 

 developed, hidden beneath the in- 

 tegument. 



Plates on breast weaker and smaller, 

 the anterior at least widely sepa- 

 rated. 



Pectoral deeply notched, the thick- 

 ened lower rays 4 in number, the 

 longest of these much produced. 



Vertical fins more anteriorly placed, 

 the predorsal length two-sevenths 

 the total to base of caudal. 



Caudal posteriorly truncate when 

 spread. 



XENERETMUS RITTERI, new species. 

 Plate 17, fig. 11. 



Type-specimen. — Cat. No. 75814, U.S.N .M., 137 mm. long, from 

 station 4366, near San Diego, depth 176 to 181 fathoms. 



Most nearly allied, perhaps, to X. latifrons, but differing from the 

 latter in the coloration, the increased number of rays in the pectoral 

 fins, the presence of two maxillary barbels instead of one, and in the 

 much stronger ridges and spines everywhere on head and body. 

 Branchiostegal membranes with an extremely narrow free-fold pos- 

 teriorly. 



Dorsal, VII, 7; anal, 7; pectoral, 16; lateral line, 41. 



Shape similar to X. latifrons, but more robust, both width and 

 depth of body greater than in that species. Head short and broad, 

 the snout even wider and more bluntly tringular than in latifrons, 

 when seen from above. Interorbital space a shallow groove, some- 

 what wider than in latifrons. A deep transverse groove behind the 

 nasal spines, one behind the eyes and one behind the occiput. Ter- 

 minal rostral plate with a single curved upright spine smaller than 

 the nasal spines; supraocular and two occipital pairs of spines, as 

 usual. Sub ocular ridge higher than in related species and bearing 

 stronger spines, two on the posterior part of the cheek and two on 

 the preopercle. No spines on margin of preopercle below the ridge. 

 Cheeks below the suborbital ridge naked, without plates or prickles. 



