BY J. DOUGLAS OGILBY. 167 



form or tubercular, few in number. One dorsal fin, with vii-viii 

 15-17 rays, the soft portion longer than the spinous; anal shorter 

 than the dorsal, with iii 10-11 rays; ventrals small, inserted a 

 little behind the pectorals, close together, with a strong spine and 

 five soft rays; pectorals moderate, rounded, with 12 or 13 rays, 

 the middle the longest ; caudal rounded or obtusely pointed. 

 Vertebrae 33 (in hemigramma). 



Etymology: — Named for the Rev. — Bostock, who made' 

 considei'able collections in West Australia from twenty-five to 

 thii'ty years ago. 



Type : — Bostockia porosa, Castelnau. 



Distribution : — Fresh waters of West Australia. 



The genus Bostockia was proposed by Castelnau in 1873 for 

 the reception of a fish found " in the small watercourses of the 

 interior of Western Australia." Since that time the genus has 

 not been again recorded until now. Castelnau has erred strangely 

 in the position to which he has assigned his new genus. He 

 remarks : — " This genus of Percidca appears nearly allied to 

 Glcmcosoma " ; the latter, however, belongs to the Lutianidce, 

 while Bostockia is a true serranid and should, I think, be placed 

 near 2facqti,aria. 



The most obvious difference between the present species and 

 Bostockia porosa lies in the formation of the lateral line, which 

 in B. hemigramma ceases at or before the vertical from the origin 

 of the anal fin, while in the typical form, according to its 

 describer, "the lateral line follows regularly the profile of the 

 back to the base of the caudal." Wei^e it not that in almost 

 every other structural character my fish resembles that of Castel- 

 nau, this difference might be taken as constituting a claim to 

 generic validity, but instances of a similar variation of construc- 

 tion are not wanting in other percoidean genera, such as Ennea- 

 canthus, Apomotis and Am,bassis, though I am unaware of any 

 such in a typical serranid. 



The two species may be synoptically arranged as below : — 

 Lateral line complete; inner ridge of preopercle serrated ante- 

 riorly; caudal fin rounded ... ... ... ... porosa. 



