1901.1 LEPIDOSlRBJSr AND photopterus. 491 



distance of 1*9 mm., and there to communicate with a Mal- 

 pighian capsule by a short channel. Beyond this point it still 

 continued backwards for 1-8 mm., and then opened back again 

 into the cavity of the testis. The tube in question may be 

 described as a vas efferens with a double origin from the testis. 

 The next vas efferens was found to arise from the testis about 

 7 mm. further back, and this one only had a single origin. 

 Another occurred 5 mm. further back, again with a double root, 

 the two roots this time, however, only '3 mm. apart, and again 

 another at a distance of 3 mm. from this one \ 



Mullerian ducts. — In a second-year male, vestiges of the Miillerian 

 duct were distinctly present. In the adult they disappear com- 

 pletely, except for the funnel at their anterior end, as described by 

 Ehlers (text-fig. 49, M.D.O.). 



Protopteeus. 



I have always found myself confronted by great difficulties in 

 endeavouring to understand the meaning of the male genital 

 organs of Protopterus as described by W. N". Parker. I was, 

 therefore, very glad of the opportunity of clearing my ideas on the 

 subject given by Mr. Budgett's kind permission to examine some 

 of his specimens of Protopterii,s. These I have examined by dis- 

 section and by the preparation of continuous series of sections 

 through the posterior region of the genito-urinary complex. In 

 the following pages I endeavour to give a short and concise 

 account of the more important points of resemblance and differ- 

 ence to the corresponding structures in Lepidosiren. 



The testis proper differs from that of Lepidosiren in its much 

 greater thickness. The formative region of the testes of a breeding 

 Lepidosiren 72 cm. in length measured 4 mm. in diameter, that of 

 a breeding Protopterus only 56 cm. in length measured 5 mm. In 

 section this difference is seen to be due to the much greater 

 length of the ampullae of the testis. Another striking difference 

 is that the vesicular region of the testis is much shorter, measuring 

 only about one ninth the length of the testis instead of about 

 a quarter, as in Lepidosiren.. Parker, as is well known, described 

 this part of the testis as a vas deferens opening into the " urogenital 

 sinus." No such opening exists here any more than in Lepidosiren, 

 even during the breeding-period. The condition is, in fact, as in 

 Lepidosire7i, except that in Protopterus the vesicular portions of 

 the two testes fuse together at their posterior ends (T , text-fig. 53, 

 & Plate XXVIII. fig. 3). 



Just as in Lepidosiren, a genital region of the kidney or posterior 

 epididymis tends to be formed ; but here the separation has become 

 much more complete, and the posterior epididymis is at once 

 recognizable in an ordinary dissection from the absence of the 



^ In tracing out the route of the spermatozoa within the kidney, I find it 

 convenient to double stain with thionin and eosin, the heads of the spermatozoa 

 being stained an intense blue, which makes them extremely conspicuous 

 against the red ground-colour. 



