460 E. RAY LANKESTER. 



EXPLANATION OF PLATES 34—37. 



Illustrating Professor Ray Lankestei's Memoir ou ''The 

 Green Piijment of the Intestinal Wall of the Annelid 

 Chsetopterus." 



PLATE M. 



Fig. 1. — Cliaetopterus variopedatus, drawn of the natural size, as 

 seen when removed from its tube. A. Anterior or ceplialic region. B. Mid- 

 region (in wliich the dark pigment occurs). C. Posterior region, a. Pinnule 

 (modified notopodium of the lllh segment). 6. Median sucker formed 

 by modification of the pair of notopodia of the 12th segn^ent. c. "Fans" 

 formed by fusion of right and left notopodia in segments 13, 14, 15. d. 

 Neuropodia of segments 12, 13, 14, 15. e. Right nephridiopore of tlie 

 15th segment. /. Notopodial cirrhi of posterior segments, ff. Neuropodia 

 of posterior segments, h. Right phosphorescent gland at the base of the 

 right pinnule. ini. Pigment of the intestinal wall showing through the 

 integument. 



Tig. 2. — Transverse section of the body of Chsetopterus variopedatus 

 taken at the point marked int. in fig. 1. (From a drawing by Dr. Benliam.) 

 a. Dorsal musculature forming a median crest or ridge, b. Transparent 

 integument, c. Connective tissue holding the gut-wall to the body-wall. 

 d. Cavity of the gut. e. Green pigmented epithelium of the gut. /. A 

 nephridium in section, ff. Ventral musculature, k. Nerve-cords. 



Fig. 3. — Epithelial cells of the gut to show the position of the green 

 granules. From a section made from a specimen preserved in formol so as to 

 avoid the solution of the green granules which occurs when alcohol is 

 employed, a. Free surface of the epithelium. 6. Branched base of an 

 epithelial cell. c. Oval nucleus. 



YiG. 4. — Some of the green granules detached from the epithelial cells and 

 more highly magnified, showing their varied size and spherical form. (Drawn 

 by Dr. Benham.) 



YiG. 5. — Absorption spectra of Chaetopterin and Bonellin as seen with 

 Sorby's micro-spectroscope. (Drawn by Dr. Benham.) Besides the shading 

 or absorption in the form of bands of greater or less breadth, the position of 

 the chief FrauenhofFer lines is indicated, and the whole spectrum is divided 

 into thirty-five spaces, the divisions between which correspond to wave lengths 

 ranging from 400 millionths of a millimetre on the right (blue end) to 750 



