SYLVIIDAE. 



they strongly incline to those eggs which — to use his own words *) — 

 ,,man der Sylvia palustris zuschreibt;" or where he further mentions 

 a set of eggs of which four belonged to the ordinary strepera-\ype and 

 one bore a pa/as/r/s-character. In both cases the description of the 

 nest and of its site points unequivocally to strepera ; the last mentioned 

 aberrant egg (depicted in Thienemann 's work— Table XXI, fig. 7, 

 sub d) is, in my opinion, wrongly rejected as a strepera-egg and 

 attributed to palustris, as I have known similar strepera-eggs. Through 

 the kindness of Mr. M. H. A. L. Merkelbach (Rolduc, prov. Limburg) 

 I saw a set of strepera-eggs (Withem, prov. Limburg, 16-VII-'09; the 

 nest and its site were typical of the species) belonging to his collec- 

 tion. Of the four eggs of this set one is spotted normally, but only 

 slightly; the other three, however, correspond both in shape and 

 marking wholly to palustris-^^s on which the black speckles occur 

 but which lack the extremely small, light grey spots occurring close 

 together (which form a characteristic of the last named species). 



When carrying out my examinations of eggshells I 

 discovered in the deeper layers of normal shells the 

 marking of the three above mentionedabnormal strepera- 

 eggs; in the case of the latter the deposition of pig- 

 ment which must take place last in the order of pig- 

 mentation (and which gives a marbled appearance to 

 eggs of a normal marking) was omitted, in consequence 

 of which circumstance their colouration remained in 

 a more original stage. 



ACROCEPHALUS PALUSTRIS (Bechstein). 



Two types can be distinguished by their markings: one in which 



l ) F. A. L. Thienemann, Fortpflanzungsgeschichte aller Vogel. (Leipzig, 

 1845-56), p. 192. 



