AUSTI;A1-1.\N (KII'.llD.K McClII,LOCII AN'1> OdIM'.V. 245 



A series of thirty-six specimens, 52-113 mm. loiif^, iiicliulin^ ^lac- 

 leay's types, indicates tliat 0. semifrenatus may be distingiiished from (I. 

 bifreiiittits by ceitaiii differences in the cohjiir-marking. (!. hifromtuH has 

 well detinetl bridle-marks, and the upper surface of the head without 

 spots; body without cross-bars; doi'sal tins longitudinally banded, and 

 the caudal witli broad bars. In (}. seniifn'juttus the bridle-marks ai-e less 

 definite, and the head is distinctly spotted above; body with cross-bars; 

 dorsal tins with oblique rows of grey s{)ols, and the caudal with small 

 interradial spots. The two species are very similar in structure, differ- 

 ing only in the form of the caudal fin, and in the disposition of the 

 anterior scales. They have been captured together in a prawn-net at Sans 

 Souci, Botany Bay, by Mr. J. H. Wriglit, but as the two forms of colour- 

 marking do not appear to be correlated with either growth or sex, we 

 regard tliem as representing distinct species. 



Lors. — Specimens are in the Australian Museum from Port Jackson 

 and Botany Bay, New South Wales. 



Uah. — New South Wales. 



Genus Rhinogobids, Gill. 



Bhinognhim, Gill, Proc. Acad. Nat. Sci. Philad., 1859, p. 145 (R. siniilix, 

 Gill). 



Body robust, compressed, covered with large ctenoid scales, which 

 become cycloid on the breast and the base of tlie j)ectoral. Head entirely 

 naked, with lines of mucigerous pores crossing the cheeks and opercles, 

 and large open pores above the nostrils, on the interorbital space, along 

 the nuchal groove, and around the preopercnlar margin. Snout obtuse, 

 the profile convex. Jaws subeqnal. Mouth a little oblique ; no barbies. 

 A band of villiform teeth in each jaw, and an outer series of enlarged 

 ones ; a snbcaniniform tooth may be present on each side of the mandible. 

 Tongue snbtruucate, and free anteriorly. Gill-openings lateral, the 

 isthmus broad. Exposed edge of the shoulder-girdle smooth. Pseudo- 

 bi'anchise present. Gill-rakers short and tliick, about five on the lower 

 limb of the first arch. Dorsal fins short, with about six spines and ten 

 rays; anal similar to the soft dorsal. Pectorals rounded, without free 

 I'ays. Ventrals large, united, with a broad basal membrane ; they have 

 one spine and five rays. Caudal rounded. 



The above definition is based upon li. nehidosas, Forskal, and A'. 

 leftwitclii, Ogilby. 



Key to the Australian species. 



a. Eye larger ; three large dark lateral blotches, scales without dark borders 



nebulosus. 



aa. Eye smaller; five smaller lateral blotches, scales with iliirk borders leflwitchi. 



Rhinogobids nebulosus, Vorslcal. 



Gohius nebulosiis, Forskal, Descr. Anim., 1775, p. 24. /(?., Bloch and 

 Schneider, Syst. Ichth., 1801, p. 72. Id., Cuvier and Valenciennes, 

 Hist. Nat. Poiss., xii., 1837, p. 84. 



