380 ENTOZOA. 



tance these markings become most distinct, appearing as bright, 

 white lines. The internal portion is composed of three different 

 sets of very dehcate lamellae, each being transparent, glass-like, and 

 structureless, with the exception of certain faint, rectilinear mark- 

 ings at regular intervals." Bastian considers these markings illu- 

 sive, and due to some structural peculiarity, involving an alteration 

 of the refractive properties of the lamellge. The simple, delicate, 

 internal, homogeneous, granular layer is not recognized by Bastian, 

 but it is, probably, the original source of aU the secretion thrown 

 out^to form the complicated external chitinous layer. The diges- 

 tive apparatus is exceedingly simple. It consists of a cylindrical 

 tube extending from the mouth to the concavity of the tail, in which 

 latter situation the anal orifice is imperceptible. Bastian says that 

 the intestinal canal winds itself several times round the genital 

 tube, is of nearly imiform size throughout its whole extent, and is 

 twice or three times as broad as the oesophagus. Eespecting the 

 reproductive organs, I have already had occasion to remark upon 

 the extraordinary development of the uterus, which, with its highly- 

 developed embryonic contents, occupies almost the entire cavity of 

 the Dracunculus. Many authors, indeed, have overlooked the very 

 existence of any ovarian or uterine tube in consequence of its inti- 

 mate union with the parenchymatous (Marksubstanz), muscular, 

 and internal integumentary layers. A little care, however, enables 

 us to separate these parts from one another, and, at least, to recog- 

 nize the walls of the uterine cavity. Sometimes the uterus, when 

 not over- distended with embryos, hes comparatively loose : at least, 

 I found this to be the case in one of the specimens preserved in the 

 Museum of the Middlesex Hospital. According to Bastian, " the 

 genital apparatus consists of a large highly-organized sac or uterus, 

 distended with young Filaria, and a little fine granular matter. It 

 occupied the whole of the peritoneal cavity in the specimens exa- 

 mined (by him), except from one to two and a-half inches from the 

 anterior extremity and about a quarter of an inch or less from the 

 tail. Both anteriorly and posteriorly this large sac terminates 



