ON CERTAIN GEEEN PIGMENTS IN INVEBTEBKATES. 431 



Fig. 3. — Spectrum of tlie acid derivative obtained by dissolviiijj the pre- 

 cipitate from an acid solution in ether, and treating the ctlier witli concentrated 

 acid. Tlie band to the right of the C line is the band of the derivative, the 

 other two are due to the presence of traces of normal chajtopterin. 



Fig. 4. — Spectrum of a solution of chsetopterin which has stood for some 

 time with ammonia; the band between those near C and D indicates tlie 

 presence of the ammonia derivative, the other four are the bands of 

 chsetopterin. 



Fig. 5. — Spectrum of the alkaline derivative obtained by allowing chseto- 

 pterin to stand for a prolonged period with dilute alkali. The solution no 

 longer contains unaltered chsetopterin. 



Fig. 6. — Spectrum of a solution of " enterochlorophyll " obtained from the 

 faeces of J'atella ; the solution contains little or no lipochrome. 



Fig. 7. — Spectrum of the same solution after the addition of hydrochloric 

 acid ; note especially the position of the band in the red. 



Fig. 8. — Spectrum of the acid derivative of enterochlorophyll intermixed 

 with a trace of the original pigment. The spectrum corresponds to that 

 figured in 3 for chsetopterin, and the solution was obtained in a similar way. 

 The second band is that of the derivative. The solution was too dilute to 

 show the band corresponding to the third band of Fig. 3. 



Fig. 9. — Section of visceral hump of Patella, showing the epithelial cells 

 of the intestine with their pigment granules, and sections of the liver tubules. 

 i. Intestine. /. L Liver tubules. 



Fig. ]0. — A few cells from the intestine, more highly magnified to show the 

 pigment granules, n. Nucleus, p. Pigment granules. 



Fig. 11. — Section of liver tubule more higlily magnified, showing the pig- 

 mented vesicles, v., and the numerous oil-drops scattered through the proto- 

 plasm, n. Nucleus. 



