2 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 93 



other types are so immature that there is doubt as to whether the 

 structures of most importance for taxonomic purposes have reached 

 a definitive stage in their development. 



Criteria for the recognition of sexual maturity in the genus Drazwda 

 are therefore essential. Size (of the specimen) is not a satisfactory 

 criterion : a worm 30 mm long may be fully mature, whereas other 

 worms well over 100 mm in length may be too small to identify. 

 Other criteria that might be suggested have proved unsatisfactory, 

 but for most taxonomic purposes sexual maturity may be regarded 

 as evidenced by the distension of ovarian segments or chambers and 

 ovisacs by free ova, the distension of the testis sacs by testicular 

 material, and the distension of the spermathecal ampullae by a floc- 

 culent, whitish material. 



Especial attention is necessary, in identifications and specific de- 

 scriptions, to the characteristics and contents of invaginations at 

 the ectal ends of the male deferent apparatus and of the spermathecae, 

 to the central body of the prostate, to the spermathecal atria, and to 

 the glands of the genital markings and the male porophores. The 

 extent of the closing off of the ovarian segment is also to be 

 determined. 



DRAWIDA GISTI Michaelsen, 193 1 



Distinguished from D. heJioensis Stephenson, 1924, by the greater 

 size of the prostates and their relation to the penis pouches, greater 

 length of the penes, larger size of the spermathecal atria, incomplete- 

 ness of closure of the ovarian chamber, presence of an " urn-shaped " 

 gland in the atrial wall, and by the definite genital markings with their 

 glands projecting through the parietes into the coelom. 



D. gisti f. typica Chen, 1933, differs from the types as follows: 

 apertures of the penial chambers located in he nearer to c than h, 

 prostates shorter, 4 to 8 mm in length (including duct) rather than 

 9 to II mm, presence of a genital marking in the penis pouch. These 

 differences may or may not be significant. 



D. gisti var. nanchangiana Chen, 1933, differs from the types as 

 follows: prostates smaller (2 to 2^ mm in length), relation of pros- 

 tates to the penial chambers, minute size of the spermathecal atria, 

 and " ventrally closer and more prominent setae ". According to 

 Chen the spermathecal atrium is " often minute, bulb-like embedded 

 in body wall, rarely elongate like other varieties ". Specimens with 

 minute atria embedded in the body wall may, of course, be juvenile, 

 but if sexually mature must be specifically distinct from forms with 

 elongate and coelomic spermathecal atria. 



