1881.] NATURAL SCIENCES OF PHILADELPHIA. 55 



1. The anterior part, or gizzard proper, a lily-shaped organ 

 composed of a spherical bowl (b.gz) and four blades or sepals, s.gz. 

 It is strongly chitinous, appears intact in all dissections, and is 

 easily seen. The crop contracts at the posterior end within the 

 four sepals of the gizzard, which thus appear to act as valves to 

 regulate or moderate the flow of aliment from the crop to the 

 stomach. What, if any, action it may have upon the food is not 

 known ; it can hardh' have the usual function of trituration, as 

 ants do not receive solid food into the crop.^ 



2. The middle part of the gizzard, or cylinder, cy.gz, is a 

 straight cylinder, with a fine, transparent internal cuticle whose 

 matrix is surrounded by a compact coat of transverse striated 

 muscles. Exteriorly the cylinder appears to merge directly into 

 the stomach. Only the muscular coat, however, is thus directly 

 continued and expanded into the fine muscular bag-net of the 

 stomach (PI. VIII, fig. b1). 



3. The internal cuticle of the gizzard traverses the walls of the 

 stomach accompanied b}- its matrix, and projects within the cavity 

 of the stomach, terminating in an elongated bulb, which is the 

 button, bn.gz. (fig. 51), bn. (fig. 59 >, or posterior part of the gizzard. 

 The anterior and posterior parts of the gizzard are always found in 

 ants, the first varying greath^, the latter scarcely at all. The cyl- 

 inder, on the contrary, is wholly wanting in many genera, and in 

 others undergoes great variations of length. The entire organ is 

 united to the crop externally by a strong muscular netting, so that 

 the two might be compared to a balloon (crop) and the car (gizzard) 

 and the enfolding muscles to the network swinging between the 

 two. 



§ 4. The Stomach. — The stomach, stm (PI. YIII,figs. 55, 56), 

 like the gizzard is alwaj'S easily discernible, inasmuch as a quan- 

 tit}^ of solid amorphous matter within it, of a dark brown or 

 blackish color, betraj^s its presence even through the segmental 

 plates. It is commonly spherical or ovate in shape. 



§ 5. Malpighian Tubes. — Around the posterior pole of the 

 stomach are grouped the Malpighian vessels, mpg (figs. 56, 60), 

 twelve in number. 



1 The various sections of the bowl appeared to me to have upon their 

 interior edges certain tooth-like inequalities, which suggested at least the 

 office of triturating or agitating the passing food. These may be, however, 

 nothing more than longitudinal flutiugs upon the external surface. 



