488 



COMPARATIVE ANATOMY 



CHAP. 



,f 



alone they may fuse to form an apparently 

 unpaired organ. Each testis consists of a 

 smaller or greater number of blind tubes 

 or testicle follicles ; these, which are 

 sometimes short, sometimes long and 

 coiled, usually lie embedded in a common 

 envelope. It may be accepted as a general 

 rule, that where the testicle tubes are 

 very long, they are few in number, and 

 vice versa. The Diptcrn and Orthoptera 

 may serve as examples of the two ex- 

 tremes. In the former (Fig. 345, A) 

 there, is on each side only one very long 

 coiled testicle tube, in the latter there 

 are often many hundred short tubes or 

 follicles united into one mass (I). The 

 testis on each side also may fall into 

 separate tubes or into separate groups of 

 tubes (c). Only one vas deferens is, 

 however, found on each side, into this 

 enter the testicle tubes united into one 

 testis, or the separate testicle tubes, or 

 the ducts of several groups of such tubes. 

 Just as the testes consist of a varying 

 number of long or short testicle tubes, 

 so each of the ovaries consists of a vary- 

 ing number of ovarian tubes, which 

 together enter an oviduct. In each of 

 these ovarian tubes (Fig. 349) we can 

 distinguish three parts : (1) the terminal 

 filament, (2) the terminal chamber, and 

 (3) the actual ovarian tube, divided into 

 chambers, this last is the largest. 



Fm. 34S. Danais archippus (Lepidoptera) 

 Female. Showing the anatomy after removal 

 of the right half of the body. Lettering of the 

 head: a, Antenna; ph, pharynx; pi, labial 

 palps ; ?, proboscis ; g, brain ; iisg, infra ceso- 

 phageal ganglion. Lettering of the thorax : 

 /, //, III, thoracic segments; &j, b 2 , &;>, the 

 coxal joints of the 3 pairs of legs ; bm, mus- 

 culature ; c, aorta cephalica with its swelling ; 

 oe, oesophagus ; bg, thoracic ganglia of the 

 ventral chord ; sd, salivary glands of one side, 

 those of the other side cut off near their entrance 

 into the common salivary duct. Lettering of 

 the abdomen : 1-0, abdominal segments ; h, 

 heart; sm, so-called sucking stomach (food re- 

 servoir); cm, chilific stomach (mid -gut); ug, 

 abdominal ganglia ; ed, hind-gut with colon (c) 

 and rectum (r) ; vm, Malpighian vessels ; ov, 

 ovarial tubes, those of the right side cut off; 

 ove, terminal filaments of the ovaries ; be, bursa 

 copulatrix ; obc, its outer aperture ; od, oviduct ; my, vagina ; v:o, its outer aperture : ad, glandular 

 appendages of the vagina partly cut away ; vl;, connective canal between vagina and bursa copulatrix 

 with swelling (receptaeulum seminis) ; an, anus (after Burges). 



Cvrv 



