On a nno Ili'torofanals and a new Vj\ivyXiCi\ 1(!7 



simply scca tlic heavy labouring of the wiiig.s as the (Ish 

 patiently whirrs along its even, uneventful way, "graceful " 

 and " light " are terms misplaced. Strenuous, persistent, 

 plodding effort is the impression left upon the mind, the least 

 failure in which eflort nutans plumping into the water. One 

 often sees this ha|)[)en obviously without intention on the 

 fisii^s part. 



In conclusion, it is, I think, made clear: — 



1. That Hying-Hsh would require to have a wing-area several 



(and probably many) times greater, according to their 

 Aveights, than they actually possess to enable them 

 to accomplish sailing flight in even such a restricted 

 form as that carried out by sailing birds. 



2. That we know of no parallel case in nature which would 



justify theassumption that the possession by these fishes 

 of even such increased wing-area would of necessity 

 enable them to sail long distances — (a) horizontally, 

 or {h) close to an obstruction (the sea), or (c) in 

 defiance of the diiection of the wind; much less all 

 three («), (6), and (c) combined, as they commonly 



3. That their common flight is exactly what is to be 



expected of flyers holding, as they do, a very low wiug 

 to weight ratio — flyers ca[)able of, and of necessity 

 employing, extreme wing-speed. 



XXII. — ^l new Heterotanais and a new Eurydiee, Genera of 

 hopoda. By Canon A. M. NouMAX, M.A., D.C.L., 

 LL.D., F.R.S., &c. 



[riates V. & VI.] 



Genus IIltekotanais, G. O. Sars. 



The genus Heterotanais was established by Sars in 18S0 

 (" Kevi.siou af Gruppen : IsopodaChelifera,^^ Arch. f. JMath. og 

 Naturv. p. 28), and four species were assigned to it : — Hetero- 

 tanais Orstedi {K\'6yQ\)^ Scandinavian; //. anoviahiSj sp. n., 

 ]\Iediterranean ; H. limicola (Ilarger), N.E. American; and 

 Jl. te/.uis (Thomson), New Zealand. More recently M. A. 

 Dollfus (" Campagnes de la ' Meliia,' Tanaid;e <SiQ.'," ^le.n. 

 Soc. Zool, de France, vol. xi. 1898, p|). M-il) has assigned 



