REPRODUCTIVE ENDOCRINOLOGY IN BIRDS 



1095 



(Munro, 1938a) . Munro found that sperm 

 obtained from the testes fertilized 3 of 69 

 liens, epididymal sperm fertilized 5 of 39 

 hens, and sperm from the vas deferens 57 of 

 77 hens. The differences between testicular 

 and epididymal sperm are statistically not 

 significant, but, in view of the lack of secre- 

 tions in vas deferens, it seems probable that 

 sperm maturation starts in the epididymis. 

 It is not known whether epididymal sperm 

 of chickens show a lower endogenous res- 

 piration rate and a greater Pasteur effect 

 than do ejaculated sperm, as is the case for 

 epididymal and ejaculated bull sperm 

 (Mann, 1954). Munro (1938b) also showed 

 that the change in the fertilization capacity 

 is not affected by androgen. Different parts 

 of the vas deferens were tied off, the birds 

 caponized, and sperm collected at various 

 intervals and tested for fertilizing capacity. 

 Androgen treatment of these capons was 

 without effect on the fertilizing capacity of 

 sperm from different parts of the genital 

 tract. This lack of effect of androgen in the 

 caponized rooster contrasts with the effect 

 of castration and replacement therapy in 

 the rat (see chapter by Bishop). 



The vasa deferentia, which become highly 

 convoluted with approaching sexual matu- 

 rity, are lined with columnal pseudostratified 

 epithelium and have three muscle layers, 

 an internal longitudinal, an intermediate 

 circular, and an exterior longitudinal layer. 

 At the distal end of the vas deferens in the 

 fowl, at the junction with the ejaculatory 

 duct, there is a small storage space, whei'eas 

 in many passerine birds large "seminal 

 vesicles" are present (Wolfson, 1954a). 

 These seminal vesicles may be organs for 

 storing sperm at lower-than-body tempera- 

 tures (Wolfson, 1954b). 



4. Vasa Deferentia 



The vasa deferentia end in the ejacula- 

 tory ducts which have numerous subepi- 

 thelial sinuses and tortuous arterioles and 

 venules in the submucosa. These structures 

 make the ejaculatory ducts erectile organs; 

 together with lymph folds, the vascular 

 body and the phallus, they form the copu- 

 latory organ (see Fig. 18.5). The phal- 

 lus is formed by a combination of two 

 roimd folds and the "white body." Dur- 



Testicular artery 



Vas deferens (exterior) 



Fig. 18.4. The connections between seminiferous 

 tubules and vas deferens according to Lake (1947). 

 (From P. E. Lake, J. Anat., 91, 116-129, 1957.) 



Fig. 18.5. Diagram of semen ejaculation in the 

 rooster (according to Nishiyama, 1955). g = longi- 

 tudinal groove of erected phaUus; / = swelled 

 lymphfold; p = erected phallus; c — papillary 

 process of vas deferens; // = 2nd fold of cloaca; 

 /// = 3rd fold of cloaca, i.e., anus; i ejection of 

 semen from vas deferens (y) and outflow of trans- 

 parent fluid from I, as well as ejaculation of the 

 semen (mi.xture of vas deferens .semen with trans- 

 jiarent fluid along g) to the outside of the anus. 

 (From H. Nishivama, J. Fac. Agric. Kvushu Univ., 

 10, 277-305, 1955.) 



ing erection the phallus becomes engorged 

 with lymph from the vascular body, whereas 

 the posterior retractor penis muscle relaxes 

 and allows the phallus to protrude. After 

 mating, the lymph can drain back into the 

 vascular bodies. The copulatory organ of 

 the turkey is distinguished from that of the 

 rooster by its lack of a midventral white 

 body and by the presence of a separate 

 white body on the tip of each round fold. 

 In colored varieties of turkeys, these white 

 bodies are highly pigmented (Lorenz, 1959). 

 An intromittent organ, a so-called penis. 



