126 Dr. Richardson's Contributions to 



Dimensions. inches, lines. 



Length of anal 9 



caudal 1 



Height of nasal cinhus \^ 



third dorsal spine 9 



thirteenth ditto 64, 



' soft dorsal 7-^ 



second anal spine 1 2 



soft anal rays 1 ' 



Height of body at pectorals 1 (> 



Thickness of ditto 8 



Therapon servus {Cuv.), Jarbua Therapon. 



Holocentrus servus, Bl. 238. Grammistes servus, Bl. Schn. p. 185. 

 Sciesna jarbua^ Shaw, Gen. Zool. iv. p. 541. 

 No. 2. Mr. Gilbert's list of Port Essington fish. 



Mr. Gilbert states that " this fish inhabits the shallow parts 

 of Port Essington. The specimen was taken from a fresh- 

 water swamp near the settlement/' and measures 6 j inches in 

 length, caudal included. The lateral line is continuous, being 

 arched until it arrives opposite to the eighth ray of the soft 

 dorsal or sixth articulated one of the anal, whence it runs a 

 straight course to the caudal, and passes a short way between 

 the bases of the middle rays. 



Therapon theraps {Cuv. & Val.), The Slave-Therapon. 



Therapon theraps, Cuv. & Val. iii. p. 131, pi. 53. 

 No. 15. Mr. Gilbert's collection of Port Essington fish. 

 At-a-goorn, Aborigines of Port Essington. 



The authors of the ' Histoire des Poissons' remark that 

 this species has a very close reseniblance to the Jarbua Thera- 

 pon (number 2. of Mr. Gilbert's list), and indeed at first sight 

 our specimen, which measures nearly eleven inches in length 

 from snout to tip of caudal, might be easily set down as merely 

 an older individual of the preceding species. Mr. Gilbert 

 however informs us that its habits are somewhat different, for 

 though abundant in the harbour it keeps in the deep water, 

 while the Jarbua seeks the shallows. An attentive com- 

 parison of Mr. Gilbert's specimens of the two species, num- 

 bers 2. and 15, elicits the following differences. 



The scales of servus are proportionally smaller, and have a neater 

 and more compact appearance, arising from their being more strongly 

 ciliated, and thereby better defined. The head has rather less ver- 

 tical height, and the eye, which is smaller, approaches nearer to the 

 profile. The suborbitar is ciliated with acute teeth, and the small 

 scales, which closely and entirely cover the cheek, abut against a 

 smooth elevated^ ridge that separates the cheek from the scaleless 

 limb of the preoperculum. In theraps the surface of the suborbitar 

 is more decidedly furrowed, but its margin is merely crenated, not 

 acutely toothed ; the interoperculum has a perfectly smooth edge. 



