JUNE 19, 1932 COBB: METONCHOLAIMUS PRISTIURUS 445 



seawater-methylene-blue the subcuticular pigment granules on the borders of 

 the longitudinal bands, already described in connection with the cuticle, mav 

 stain green at a time when the rest of the granules stain blue. This appear- 

 ance is similar to what is now being described for the unstained nema; so that 

 the structure of the lateral cords is now shown to be in harmony with that of 

 the longitudinal bands of subcuticular pigment. In other words, the arrange- 

 ment of the pigment granules of the cuticle is doubtless in some way correlated 

 with the arrangement of the cells in the lateral cords beneath. The proto- 

 plasmic network in the cells of the lateral cords is considerably finer than the 

 protoplasmic network in the outer part of the cells composing the intestine, 

 but nevertheless, has the same general appearance. The lacunae among the 

 strands of the network are of variable size, more or less equidiametral, 

 though never exactly so; polygonal, but not regularly so. The lateral cords 

 are wellsprings of the cuticle. 



The granules of the subcuticle, 34, 82, 95, differ from the yellowish gran- 

 ules contained in the network of the cells of the lateral cord; in the specimen 

 under examination the granules in the subcuticle (a little under one micron) 

 are more nearly colorless and are round, whereas those in the lateral cord are 

 yellowish, and somewhat irregular in size and form. 



Renette and excretory pore. The excretory pore, 58, is located about one- 

 fourth the distance to the nerve-ring on the ventral side of the neck. The 

 nucleated single renette cell, 68, about four body-widths behind the neck, is a 

 fusiform, granular, ventrad cell, about twice as long as wide, and nearly two- 

 thirds as long as the corresponding body diameter; the renette duct, 60, 67, 

 leads from it, somewhat meanderingly, forward to the excretory pore, and is 

 readily seen, as a rule, or at least some of it is. It is a slender tube about 

 one-twentieth as wide as the neck and ends anteriorly in a small ellipsoidal 

 ampulla, near 58, nearly one-third as long as the neck is wide, emptying 

 outward through the ventral excretory pore in the cuticle by means of an ex- 

 ceedingly narrow duct only three to four microns long. The excretory secre- 

 tion of this gland, as seen in its duct, and ampulla, is granular, the uniform, 

 spherical, colorless granules being about one micron in diameter. This 

 entire apparatus, the renette, is regarded as excretory in function. 



Nervous system. An important part of the central nervous system is the 

 nerve-ring, 38, about ten microns wide, surrounding the oesophagus somewhat 

 obliquely in front of the middle. It consists of a compact network, or skein, 

 of exceedingly fine nerve fibers. Before and behind the nerve-ring are scores 

 of distinct nucleated ganglion cells, 11, 56, etc., mostly bipolar, those in frort 

 being arranged in eight obscure longitudinal groups, two lateral, one ventral, 

 one dorsal, and four submedian. The ganglion cells are variously connected 

 with each other and with the nerve-ring. Placing the nema over night in 

 seawater-methyl-blue discloses some of the elements of the ventral nerve 

 leading from the nerve-ring along the ventral line to the tail. Usually about 

 128 fusiform elements in the ventral series may be disclosed (stained blue) 

 in this way. These can be proved to be connected with each other. The 

 same treatment is likely also to reveal the nerve elements entering the bases 

 of setae, and papillae, especially in the tail of the male. See Fig. 4. 



Female organs. From the slightly elevated vulva, 7, which is a transverse 

 ventral slit of moderate size, the medium sized vagina leads inward and 

 slightly forward about halfway across the body; the vagina is somewhat 

 cuticularized and is accompanied by small and very inconspicuous vaginal 

 glands, 9, fore and aft. About two dozen radiating muscles, 6, occur around the 



