040 3UR H. SAUNDERS ON THE STEKNIN.E. [JuilC'20, 



of the bill — a very variable character in Terns, and one which, wben 

 taken alone, does not seem to be of so much value in this family as 

 in many others. 



All things considered, the following arrangement of the various 

 species seems to me to be the most natural ; but, as is well known to 

 all naturalists who have undertaken a similar task, it is impossible 

 to attain to absolute consistency in locating the various members 

 of a family in an ascending or descending scale ; for the aberrant 

 forms which frequently present themselves would destroy the best 

 scheme that ever could be invented. 



Genus Hydrochelidon, Boie. 



This genus, originally instituted by Boie (Isis 1822, p. 563) for 

 77. nigra and H. leucoptera, H. hybrida being left by him with 

 Sterna, was, indeed, principally based upon coloration ; but it has 

 since been well defined and generally accepted as including the Marsh- 

 Terns — of which the most characteristic distinctions are the short 

 rounded tail, and the long slender toes connected by deeply incised 

 webs. There is a general resemblance between the species which 

 compose this very natural genus, the members of which agree in 

 their habits, being gregarious at the breeding-season, and making 

 their nests in the midst of marshy places. For convenience of 

 treatment I commence with 



Hydrochelidon hybrida (Pall.). 



Sterna hybrida, Pall. Zoogr. Ilosso-As. ii. p. 338 (1811); Schlegel, 

 Mus. P.-B. Sterna, p. 33 (1863). 



Sterna leucopareia,~Natterer, inTemm. Man.d'Orn.p.746 (1820). 



Sterna javanica, Horsfield, Trans. Linn. S. xiii. p. 1 98 (1820) (type 

 examined in E. I. Mus., H.S.); Gray & Hardw. lll.Ind. Zool.i.pl./O. 

 fig. 1 (1832). 



Sterna grisea, Horsfield, Trans. L. S. xiii. p. 199 (1820) (type ex- 

 amined in E. I. Mus., H. S.). 



Viralva indica et V.leucopareia, Steph. in Shaw's Gen. Zool. xiii. 

 p. 171 & 109 (1825). 



Sterna delamottei, Vieillot, Faun. Fr. p. 402(1828). 



Pelodes leucopareia, Kaup, Nat. Syst. p. 107 (1829). 



Sterna similis, Gray & Hardw. III. hid. Zool. i. pi. 70, fig. 2 (1832) 

 (type examined in E. I. Mus., H. S.). 



Hydrochelidon fluviatilis, Gould, P. Z. S. 1842, p. 140 ; Gould, 

 B. Australia, vii. pi. 31 (1848). 



Hydrochelidon hybrida, G. R. Gray, Gen. B. iii. p. 660 (1846) ; 

 Bias. J. f. Orn. 1866, p. 82; Degl. & Gerbe, Orn. Eur. ii. p. 4(i8 

 (1867); Swinhoe, P. Z. S. 1871, p. 421 (Formosa). 



Hydrochelidon delalandii, Bp. Compt. Rend. xiii. (1856), p. 773 

 (type examined, H. S.). 



Hydrochelidon indica, Jerdon, B of India, iii. p. 837 (1864). 



Hydrochelidon leucopareia, Gould, Handbook to B. Australia, ii. 

 p. 406 (1865). 



