204 



HARD WICKK S S CIENCE ■ G O SSIP. 



any intestine. The eyes were black, and are repre- 

 sented by the two dots at the anterior end of the 

 muscular pharynx. The integument was studded 

 with trichocysts, and at the posterior end of the body 

 a number of well-marked processes were observable, 

 which perhaps serve purposes analogous to those 



128. — A Turbellarian Worm. 



, s 



1000 

 I 



270 



Fig. 129. — Animalcules obtained from scum, a, Vorticella ; b^Avtceha radiosa ; 

 c, d, e, Amoeba at intervals of about ten minutes ; _/) Paramecium. 



served by the terminal 

 species of Chcetonotus. 



drawing, 



toes of rotifers and various 

 As will be seen from my 

 the animal did not possess a distinctly- 

 marked head, and the body was variable in form ; 

 but, so far as I observed the worm, the anterior end 

 was always broader, and perhaps flatter, than the 

 posterior extremity. The same mass of decaying 

 matter teemed with nematoid worms, which seemed 

 to be passing an active and merry existence in 

 working their way through the decaying cells of the 

 ceratophyllum. 



W. J. Simmons. 

 Calcutta. 



THE FERTILITY AND COLOURING OF 

 BIRDS' EGGS. 



FROM carefully observing the eggs of the common 

 sparrow for four consecutive seasons, there can 

 be no doubt that the percentage of fertility influences 

 the colouring ; or, in other words, the greater the 

 fertility, the darker the colouring of the eggs. 



In looking over a scries of clutches of the eggs of 

 the blackbird, it cannot fail to be observed that in 

 every clutch there are two types of egg, one type 

 being of a darker colour than the other. 



Wishing to see if the fertility of these light-coloured 

 eggs was under the same influence, I made the fol- 

 notes on thirteen clutches which I was per- 



lowing 



sonally able to observe, and at the same time I 

 endeavoured to test the theory, or statement, that 

 " the light-coloured egg which is often seen in a 

 clutch is the last laid, and light in colour from the 

 colouring matter becoming exhausted." To do this- 

 I had to mark the eggs as they were laid, but un- 

 fortunately I could only carry this out in- 

 seven clutches. 



The following notes do not give a very- 

 satisfactory result with regard to the fer- 

 tility and the colouring, but I think they 

 clearly demonstrate that the light-coloured 

 egg in a clutch is not light in colour from 

 the colouring matter having become ex- 

 hausted. 



There does not appear to be any rule as 

 to the order in which the light-coloured 

 eggs are laid, but very commonly there is 

 a light-coloured egg amongst the first 

 three laid, and these light-coloured eggs 

 are generally a few grains heavier ia 

 weight than the darker ones. 



The following gives the particulars of 



the thirteen clutches under observation : — 



March 19.— Eggs, four ; all light in, 



colour ; first and third the lightest ; all 



infertile. 



March 25. — Eggs, four; three dark eggs, 

 one light. This brood died in the nest, pro- 

 bably from the cold. One infertile egg. 

 25. — Eggs, three; the first the lightest- 

 coloured egg. All these were fertile. 



April 15. — Eggs, five ; four eggs of the normal 

 colour, one very light. 



April 15.— Eggs, five; three dark, two light. In 

 this clutch the lightest-coloured eggs weighed 12a 

 grains each, the dark ones 118 grains each. 



April 20. — Eggs, three; one egg light in colour;, 

 all fertile. 



April 20. — Eggs, five ; three dark, two very light. 

 April 20. — Eggs, four ; three dark, one light. 

 April 22. — Eggs, three ; second egg laid the 

 lightest. 



April 24. — Eggs, four ; first and fourth light eggs.. 



April 28. — Eggs, four ; first and fourth light eggs. 



May 6.— Eggs, four; the three first laid light ia 



colour, the fourth darker and very much flecked ; 



this egg infertile. 



May 13. — Eggs, six. In this clutch the first four 

 were typical eggs of the blackbird ; the fifth egg 

 very light in colour ; the si.xth egg dark, and very 

 much coloured at the small end. These eggs were 

 all fertile excepting the fourth, which showed na> 

 signs of fertility. This clutch was laid by the same 

 bird, and in the same nest, as the clutch dated 

 March 25. 



These clutches may appear to some of your readers 

 to be short, but in this locality a si.v clutch is quite 

 the exception, the one I have remarked upon being 



March 



