ACCESSORY MAMMALIAN REPRODUCTIVE GLANDS 



373 



anterior, or outer and inner (medullary). 

 The component parts of these regions have 

 been discussed extensively (see Moore, 

 1936; Huggins and Webster, 1948; Retief, 

 1949; Franks, 1954). Lowsley (1912) 

 studied the embryologic development of the 

 human prostate and concluded that the 

 gland derives from five independent groups 

 of tubules. A cranial posterior or dorsal 

 group (lobe) arises from the dorsal wall of 

 the prostatic urethra or urogenital sinus; 

 right and left lateral lobes originate from 

 the prostatic furrows and grow back to form 

 the main part of the base of the gland; a 

 middle lobe derives dorsally from the ure- 

 thra between the bladder and ejaculatory 

 ducts; a ventral or anterior lobe forms but 

 regresses and becomes insignificant. 



Although these prostatic buds or tubules 

 form independent groups in their embryonic 

 origin there is no clear separation into such 

 groups in the human prostate postnatally. 

 However, Huggins and Webster (1948) were 

 able to distinguish clearly two different re- 

 gions, a posterior and an anterior lobe, by 

 differential response to estrogen adminis- 

 tration. The extent of the anterior or ventral 

 lobe, as delimited by them, apparently in- 

 cludes the tubules of the middle and lateral 

 lobes as described by Lowsley. 



The pioneer studies of Walker (1910a) on 

 the coagulating function of discrete glands 

 of the prostatic complex in rats and guinea 

 pigs (Fig. 6.3) were followed by specific 

 identification of coagulating glands in sev- 

 eral rodents including mice and hamsters 

 (Fig. 6.2) and in the rhesus monkey (van 

 Wagenen, 1936). However, a copulation 

 plug in the vagina of females has been re- 

 ported in some marsupials, insectivores, 

 chiropterans, the chimpanzee among the 

 primates (Tinklepaugh, 1930), and several 

 genera of rodents in which coagulating 

 glands have not been identified. Eadie 

 (1948a) found that in an insectivore, Con- 

 dylura cristata, there is a peculiar prostatic 

 secretion from paired ventral lobes. It con- 

 tains an enormous number of amyloid 

 bodies resembling the corpora amylacea 

 present in the prostate gland of man and 

 some other mammals. These prostatic con- 

 cretions are generally considered abnormal, 

 but Eadie suggested that this unusual se- 



cretion, which was found in all breeding 

 males, might be instrumental in the forma- 

 tion of a unique type of copulation plug. 

 A large ''urethral" gland which lies be- 

 tween the prostate and bulbo-urethral 

 glands and surrounds the urethra is peculiar 

 to certain species of bats. Mathews (1941) 

 considered it probable that the presence of 

 this gland is correlated with the formation 

 of a large copulation plug, but he did not 

 ascribe a specific coagulating function to 

 the gland (which bears a histologic resem- 

 blance to the bulbo-urethral glands in some 

 bats). 



The difficulties of homology and classifi- 

 cation can be illustrated by the case of the 

 rabbit. Differences of opinion have existed 

 concerning the nomenclature and homolo- 

 gies of the seminal vesicles (or prostatic 

 utricle), vesicular glands (seminal vesicle 

 or prostate), and paraprostate glands (or 

 superior Cowper's glands). In studies on 

 embryologic development and histologic 

 structure, Bern and Krichesky (1943) clari- 

 fied the problem. They established that the 

 domestic rabbit has true seminal vesicles, 

 vesicular glands (which are considered as 

 probably homologous with the coagulating 

 glands of rats), prostates, paraprostates 

 (usually similar to the bulbo-urethrals in 

 histologic structure but in about one-third 

 of the cases, one or more of the parapros- 

 tates resembled the prostate histologically), 

 bulbo-urethral glands, and glandular am- 

 pullae. Elschlepp (1952) compared the ac- 

 cessory glands of the cottontail, Sylvilagus 

 floridamis, with those of the domestic rab- 

 bit, and concluded that coagulating glands 

 (avoiding the usage of "vesicular glands" 

 which has often been used synonymously 

 with seminal vesicles) , dorsal prostates, and 

 bulbo-urethral glands are homologous in 

 the two species. The adult cottontail has 

 neither paraprostates nor seminal vesicles 

 (Fig. 6.4) . Classification of the glands in the 

 hedgehog and shrew has also presented 

 problems (see discussion in Eckstein and 

 Zuckermann, 1956; Eadie, 1947). Among the 

 Sciuridae, many possess a bulbar gland 

 which differs from their true Cowper's 

 glands (Mossman, Lawlah and Bradley, 

 1932). It is evident that among mammals 



