THE EXTERNAL GENERATIVE ORGANS. 741 



A saddle-shaped plate, which unites the paraphalli at their 

 proximal end, supports a curved spine, the epiphallus, and gives 

 articulation to a pair of small palp-like organs, which I term 

 the posterior gonapophyses. 



The penis when at rest in the genital pouch lies in the 

 median plane and has its long axis at right angles to the axis 

 of the abdomen ; its dorsal surface looks backwards and its 

 ventral surface forwards. When it is exserted from the genital 

 pouch its extremity is directed forwards, its ventral surface 

 upwards and its dorsal surface downwards. 



In describing its several parts I shall regard it as exserted. 

 The hypophallus in this position is above the ejaculatory duct 

 and penis proper, the paraphalli curve upwards ; the inner and 

 outer valves of the genital pouch are below and behind the 

 penis, and are directed forwards ; and the dorsum of the meta- 

 genital somite looks downwards. 



In fact, the whole extremity of the abdomen is curved when 

 exserted, so that its extremity is directed forwards. To apply 

 the description of the several parts to the penis when with- 

 drawn it is only necessary to read backwards for downwards, 

 and forwards for upwards. 



The Hypophallus is a broad plate, convex below and concave 

 above ; its edges are serrated, with the serrations directed 

 backwards. It is the ventral wall of the penis proper. Two 

 spine-like processes, the cornua, project upwards. It articu- 

 lates behind with the ventral processes of the paraphalli, and 

 in front by its cornua with their extremities. In front of the 

 cornua the hypophallus is prolonged as a median spine, which 

 supports the extremity of the penis. 



The Paraphalli form a saddle-shaped sclerite under the proximal 

 fourth of the dorsum of the penis. This saddle bears a strong 

 curved azygos spine. The anterior edges of the saddle are 

 prolonged as two long hollow hooks, which are broad at their 

 base. A wide curved process embraces the penis and unites 

 with its fellow on its ventral aspect. These processes of the 

 paraphalli support the posterior edge of the hypophallus, with 

 which they articulate by syndesmosis. 



