2340 Bulletin 4.7, United States National Museum. 



867. ARBACIOSA, Jordan & Evermann. 



Arbaciosa, JORDAN & EVERMANN, Proc. Cal. Ac. Sci. 1896, 290 (humeralis.) 



This genus differs from Gobiesox chiefly in the character of the incisor 

 teeth of the lower jaw; these are strongly serrate, or tricuspid, making a 

 ragged cutting edge. Size small; dorsal and anal comparatively short ; 

 head not very broad, the jaws contracted; vertebrae (in Arbaciosa zebra) 

 28. Some species provisionally referred to the section Sicyases of Gobiesox 

 may prove to belong to Arbaciosa; small species, living in rock pools, 

 among the sea urchins, by whose spines they are protected. This relation 

 of Arbaciosa zebra with the Echinoid Arbacia stellata is especially constant. 

 (Arbacia, a sea urchin.) 



a. Anal fin long, about 10 rays ; dorsal rays 11 ; teeth above in 1 series ; color olivaceous. 



EHESSODON, 2682. 



aa. Anal fin of 5 to 7 rays. 



6. Dorsal fin of 8 or 9 rays; teeth in single series; color brownish, with red bars 



and a large black humeral spot. HUMERALIS, 2683. 



bb. Dorsal fin of 7 rays ; color greenish, with pale spots and numerous pale cross 



bands; no red; body slender. RUPESTRIS, 2684. 



bbb. Dorsal fin of 6 rays ; color chiefly red. 



c. General color pinkish olivaceous, with some bright red; back with 5 

 reddish-brown or blackish bars. Upper teeth in more than 1 series. 

 Body comparatively slender, the depth nearly 8 in length. 



ZEBRA, 2685. 



cc. General color bx'ight rosy red, black, with 1 to 3 faint dark bars. Upper 

 teeth nearly uniserial. Body comparatively stout, the depth 5j in 

 length. EOS, 2686. 



2682. ARBACIOSA RHESSODON (Kosa Smith). 



Head 3J; depth 6. D. 11; A. 10; eye 4 in head, f in interorbital 

 space ; ventral disk 1 in head ; pectoral 2 ; caudal 2. Form much as in 

 Gobiesox mceandricus ; snout bluntly and evenly decurved; the greatest 

 height of the body across the pectoral fins; head broader than body but 

 less deep; maxillary extending to below the eye; incisors of lower jaw 

 not much declined, each of them tricuspid, the central cusp longest ; teeth 

 of upper jaw conical, in an irregular series of 7 to 9; teeth in each jaw 

 in single series ; opercular spine sharp' ; distance from vent to caudal 2f 

 in length of body ; dorsal a little longer than the anal, having its origin 

 in advance of the anal and terminating opposite it; caudal rounded. 

 Color dark olivaceous, usually with 3 broad yellowish cross bands above, 

 the first across interorbital space and cheek, the second very wide, across 

 back and front of dorsal fin, the third below middle of dorsal, some or 

 all of these sometimes wanting ; a dark bar at base of caudal ; belly yel- 

 lowish. Length 2 inches. San Diego to the northern part of the Gulf 

 of California; locally abundant in rock pools, (prftidc*), to make ragged; 

 6dov$, tooth.) 



Gobiesox rhessodon, ROSA SMITH, Proc. U. S. Nat. Mus. 1881, 140, San Diego, California; 

 JORDAN & GILBERT, Synopsis, 749, 1883; ROSA SMITH, Proc. U. S. Nat. Mus. 1883, 235. 



