(■|(»4 Mil. U. II. WIIITKIIorsE (IN TIIK [Apr. 5, 



II A I- 1, (I M 1. 



Gal.WIAS <<i>.'^. (Ci:ilaxii(la\) 



Only :i .sinylo spocinien wa.s ;iv;iilal)le for cxaiiiinatiou ; tlii.s 

 revealetl a free luu.style, beyond wliioh tin- notocliunl continueil 

 for some distaiicp, hut did not reach the deriiiotrichia. Seven 

 hypuraLs are pre.sent, five of wiiich are attached to the last 

 vertebral segment ; the hist three are closely applied to each other 

 and so form a large plate. Dorsally the deriiiotrichia are supptirted 

 by two epural bones and a dorsal caudal radial, the hitter being 

 cartilaginous. Both the epnrals and liypnrals of the penultimate 

 and antepenultimate vertebiw are very liroadly expanded, and 

 show traces of the inclusion of radials in their formation. Tlu^ 

 la.st vertebra possesses a small neural arch and the s})inal cord can 

 be traced to the end of the notochord. tSuch a caudal iin must 

 be considered a lowly specialized form of homocercy. 



No o-eneraliz<ltions can be made on the Hapiomi until more 

 species have been e.xamined, 



II i:t k a o m I. 



FiERASFER ACL'S, (Fierasfcrida',) 



In this fish the median fins fire continuous. At the extreme 

 end of the tail no fin-rays are present in the fin-fold, so that there 

 is a gap between the fin-rays of the dorsal and ventral fins. The 

 vertebral column ends in a perfectly stiaight line. and. towards 

 the end, consists of alternate segments of centra and notochord, 

 the final element being notochoi'd which comes in contact with 

 the integument. The fin is therefore perfectly symmetrical 

 externally and internally and moreover sho\vs obvious signs of 

 degeneration, llyder concludes that the whole of the true caudal 

 has been lo.st, and hence the tail is truly gephyrocercal. It is 

 interesting to note that the developmental stages do not reveal 

 any heterocercal tendencies. 



FiEUASFliR DENTATUS. {KcJuodou. dentatus.) (Plate XLVIII. 

 fig. U.) 



The figure of the tail of this .species gi\ eu by lOnu'ry is most 

 interesting as presenting a typical gephyrocercal tail. The laiva 

 is [)rovided with a long filamentous tail-ending, which is eventu- 

 .•dlv lo.st in some way, and the adult tail gives the appi-arance of 

 having had the end bitten off; the vertebral column ends in a 

 vertebra exactly similar to the preceding ones ; tlie dorsal and 

 ventral fin-rays attempt to bridge over the gap caused by the loss 

 of the caudal extremity, but never actually meet. The fin-rays 

 of the dor.siil and anal fins are supported by wry small cartilages 

 which represent radials, and which are far removed from the axis, 

 I have not yet had an opportunity of examining t liis caudal Iin, 

 and .so 1 reserve anv remaiks on this remarl<al)|c tonii. 



