ICHTHYOLOGICAL NOTES (iVo. 4)—0GILBY. 



99 



{Giiicliii')/^ measuring 128 mm., a Pseiws wliitclcggii Waite," two of the beauti- 

 ful RliiidinoccnirHS ornatus Regan," which appears to be confined to Moreton 

 Island, and two of the above symbranchs. Though certain differences between 

 these specimens and the descriptions of M. albus were perceptible, I considered 

 it advisable, owing to the absence in this Museum of examples for comparison 

 and the veiy small size (135 and 120 mm.) of thi.s pair, to send them to Mr. 

 McL'ulloch for further examination, and I give liere the very interesting notes 

 which he has kindly forwarded to me on the subject: — "An examination of 

 your two snudl Motiopteni^ does not enable me to identify them as M. albus, 

 with three of which 1 have compared them. They appear generally similar, 

 but the gill-opening is much farther back in your specimens; in alMiS it is in 

 advance of the origin of the lateral line, and in yours well behind that point. 

 I can think of no more satisfactory way of expressing the character. Again 

 your specimens have distinct caudal rays, whereas the others have none, but this 

 is perhaps due to their very small size. The teeth in your specimens are villi- 

 form, in a band in each jaw which is fairly wide anteriorly, but becomes very 

 narrow laterally; they form a small forward projection at the premaxillary 

 symphysis. They api^ear to be biserial on each palatine anteriorly, becoming 

 nnisei-ial posteriorly. They are evidently quite similar to those of M. albus." 



The following table of comparative measurements is drawn up from 

 the measurements of the five specimens kindly taken by Mr. McCulloch^ 

 following Daj' : — 



Head to head and trunk 

 Tail to total length 

 Eye to head 

 Eye to snout . . 



Moreton 



Bay, 



135 mm. 



I. 17/2835. 



6-5 

 3-3 

 11-6 

 2-13 



Moreton 



Bay, 



120 mm. 



I. 17/2836. 



6-5 

 2-75 

 11-5 



2 



waters. 



This is the first record of the occurrence of this genus in Australian 



SILURID.E. 



HEXANEMATICHTHYS AUSTRALIS (Guntlier).'" 



Some time ago the Bluseum received the head of a very large catfish 

 belonging to this species, which had beeu caught in the Burnett River. In an 

 MS. description of the "Estuary Catfish," drawn up from an examination of 



" Gobius gronoini GmeWn, Syst. Nat., i, 1788, p. 128. I scarcely think it advisable to 

 substitute the generic name Gobiomorus for that used here ; v. Jordan, Guide to tlie Study of 

 Fishes, ii, p. 285. 



»J Proc. Linn. Soc. N. S. Wales, xix, 1894, p. 218, pi. xvii, fig. 1. 



" Trans. Zool. Soc. London, xx, 1914, p. 280, pi. xxxi, fig. 1. 



•^ Arius australis Giinther, Proc. Zool. Soc, 1867, p. 103, c. text-fig. of upper surface of 

 head. 



