1090 



SUBMAMMALIAX VERTEBRATES 



Fic. 18.6. Penis of duck according to EUenberger 

 and Baum (1932). a = cloaca; /) = penis; c - 

 seminal groove ; d — ridge of seminal groove ; e = 

 opening of glandular tube; / = opening of vas 

 dejerens; g = opening of ureter. (From W. EUen- 

 berger and H. Baum, in Handbuch der Verglei- 

 chenden Anatomie der Havstiere, 17th ed., Julius 

 Springer Verlag, 1932.) 



is found in Anseres, Cracidae, Crypturi and 

 Ratitae (Domm, 1939). Figure 18.6 illus- 

 trates the "penis" of a drake. The semen 

 is transported along the seminal grooves. 

 Stimulation of the nerves originating from 

 the sympathetic plexus and going to the 

 lymph folds has resulted in erection of the 

 penis of drakes (Domm, 1939). The time 

 sperm require to traverse the duct system 

 from testis to phallus has been estimated 

 as 24 hours in an active rooster and 2 to 3 

 days in a sexually inactive one (Munro, 

 1938a). 



The enormous variation of the morjihol- 

 ogy of sperm from different species is il- 

 lustrated in Figure 18.7. The various factors 

 which may affect sperm morphology after 

 ejaculation will be discussed later. 



The finer structure of the fowl sperma- 

 tozoon has been investigated with the aid of 

 the electron microscope (Grigg and Hodge, 

 1949; Bonadonna, 1954). The results can 

 be summarized as follows: At the anterior 

 tip of the head there is a small acrosomal 

 spine which is embedded in the head proper. 

 This spine is 1.5 X 0.1 ix m size and is 

 covered by an acrosome cap. The head of 



the sperm has dimensions of 14 X 0.5 /x, and 

 is slightly curved. After eosin-nigrosin 

 staining a crescent-shaped proximal cen- 

 triole can be seen at the posterior end of the 

 head (Lake, 1954). This centriole does not 

 stain in fresh semen regardless of the mor- 

 phology of the sperm, but after storage of 

 sperm at 5''C. all abnormally shaped sperm 

 show a deeply stained proximal centriole 

 even when the head has not taken up the 

 stain. Occasionally a normally shaped 

 sperm will also show a stained proximal 

 centriole (El Zayat, 1960). The midpiece, 

 between the head and tail, measures 4 X 0.5 

 IJL and is bounded anteriorly by the anterior 

 distal centriole, posteriorly by the posterior 

 distal centriole. Fibrils of the tail filament 

 arise from the anterior distal centriole, pass 

 medially through the midpiece, and pass 

 through the posterior distal centriole. The 

 tail, which starts at the midpiece tail junc- 



FiG. 18.7. Spermatozoa of different sjiecies of 

 birds (according to Romanoff, 1959). 1 — Chicken 

 (Gallus gallus); 2 — pigeon {Columba livia) ; 

 3 = turkey (Meleagris gallopavo) ; 4 — duck {Anus 

 platyrhynchos) ; 5 = sea duck {Aythinae); 6 — 

 ring-necked parrot {Psittacus torcuatus) ; 7 = 

 black-headed gull (Lams fuscus) ; 8 — red-backed 

 sandpiper (Calidris alpina) ; 9 = European wood- 

 cock {Scolopax rusticula) ; 10 — European coot 

 {Fulica atra); 11 — European ruff {Philomachus 

 pugnax); 12 — sparrow (Passer domesticus) ; 13 — 

 greenfinch (Chloris chloris) ; 14 = .songthrush 

 (Turdus philomelos); 15 — chaffinch {FringiUn 

 coelcbs). Magnification 600 X. (From A. L. Ro- 

 manoff, The Avian Embryo, Macmillan Company-, 

 1960.) 



