MALE GENITAL SYSTEM: INTERNAL ORGANS 383 



also found a similar pit. Meek (19 18) found no trace of a uterus masculinus in Delphinus 

 delphis — he saw only a single crescent-shaped aperture on the verumontanum leading 

 into the separate seminal ducts, which are separated at their terminations by a septum. 

 Anthony, however (1922), found traces of a uterus masculinus in this species in the form 

 of a pair of small ducts bordering the vasa deferentia near the testes. 



The uterus masculinus or sinus pocularis represents the vestiges in the male of the 

 Miillerian ducts and has been given a variety of different names. It finds its fullest 

 development, according to Weber (1904), in the Rodents, Ungulates and some Car- 

 nivores, where it has the form of a central canal between the vasa deferentia ending in 

 two lateral horns. In this condition it resembles the uterus bicornis of the female and 

 may correctly be called a uterus masculinus. In the narwhal (Owen, 1868, vol. m) and 

 in many Ungulates (the horse, the donkey and the zebra) the Miillerian system is 

 represented by a caecum between the vasa deferentia bifid at its extremity. Weber gives 

 to this condition the term vagina masculina. In Primates, many Carnivores and 

 Insectivores it presents the condition described for Balaenoptera by Daudt — a small 

 unpaired cavity surrounded by the prostate gland. In this condition Weber gives the 

 structure the terms sinus pocularis, sinus prostaticus or vesicula prostatica. 



Among the Cetacea in general the Miillerian system in the male appears to represent 

 a considerable variety of conditions. In describing the verumontanum of Kogia 

 breviceps, Benham (1901) says: "the pores (of the vasa) are quite below the general level 

 of the mucous membrane and between them is a very slight recess in the substance of 

 the urethral wall which no doubt represents the uterus masculinus". From this one 

 may proceed to the condition described by Daudt and Beauregard and Boulart, already 

 mentioned, in Balaenoptera and thence to that found by Meek in the porpoise (Phocaena 

 phocaena). Here the uterus masculinus has the form of a single blind tube — a vagina 

 masculina — lying between and behind the openings of the vasa deferentia. The single 

 cavity in Phocaena may show two openings. In other Odontocetes the uterus masculinus 

 was found by Owen (1868, vol. 111) in the narwhal, where it was a vagina masculina — 

 an elongated caecum opening behind the seminal pores — and by Meek (19 18) in 

 Beluga (now Delphinaptenis) leucas, where it was stretched out into a flattened cavity. 

 In the Lagenorhynchus described by Meek (an abnormal specimen) there was a short 

 Miillerian duct on each side fusing medially into a sinus. In Mesoplodon the 

 Miillerian system, according to Anthony (1922), reaches its greatest development among 

 the Cetacea. There are two long Miillerian ducts which have the form of cords, with a 

 narrow lumen terminating in a cul-de-sac at the extreme tip. The cords begin on each 

 side at the posterior extremity and internal border of the testis, and pass along the wall 

 of the vaginalis testis and thence accompany the vasa deferentia through the vagino- 

 peritoneal canal, which exists in Mesoplodon. The two ducts join in the inter-deferential 

 mesentery and form a cord passing between the two vasa. This cord has at first a large 

 cavity which dwindles rapidly backwards and soon disappears. There is thus no opening 

 of the uterus masculinus on the verumontanum. In Delphinus delphis — in which Meek 

 found no uterus masculinus — Anthony found only the distal parts of the Miillerian 



