10 Transactions of the Society. 



expressly states his complete adherence to Claparede's opinion, 

 extending it to Tromhidium* On the other hand Leuckartf con- 

 sidered that a similar tissue in the leach was not hepatic, and Ledig 

 in his histology agreed in this with Leuckart, and the more recent 

 investigations of Professor E. Eay Lankester :!: would seem to point 

 rather to a blood-elaborating function for this " botryoidal " tissue. 

 I have not been able to find any salivary glands nor any 

 appendages to the hind- gut. 



The Beproductive System. 



This, next to the alimentary canal, is the largest and most 

 important set of organs in the body ; the general arrangement is 

 very similar in the two sexes. When the notogastral shield has 

 been removed, the genitalia may be seen lying at the sides of the 

 canal, and in some instances, in the female, when the oviducts are 

 distended with eggs, they seem to have usurped the place of almost 

 all the other organs, and to have pushed them out of position. 



The Male Organs of Generation. — These consist of a large 

 central testis, or more probably one on each side, coalescing in the 

 median line by being imbedded in, and united by, a flat mass, which 

 appears to perform the double office of increasing the quantity 

 of the secretion and acting as a vesicula seminalis ; two vasa 

 deferentia, a ductus ejaculatorius, a penis with its accessory organs, 

 and three pairs of copulative suckers. 



The testis, treating the whole as one organ, is very large, 

 sometimes appearing to half fill the body and force its lobes up to 

 the notogaster ; it usually extends the whole width of the body, 

 and forms a saddle-shaped mass, which underlies the ventriculus in 

 the centre, there constituting an almost flat layer of considerable 

 thickness, deeply indented, both anteriorly and posteriorly, as 

 though it were two paired organs which have met and united ; no 

 sign of suture or demarcation is however visible there (plate II. 

 fig. 1, a, h). In addition to this, each side has a tendency to be 

 bilobed, and the anterior lobe, which is part of the flat mass, in 

 some species, or at some periods, rises much nearer to the dorsal 

 surface than the posterior one ; the whole varies somewhat in form 

 in difierent species, in Nothrus theleproctus the anterior lobes are 

 large and rounded, in Orihata laindaria they are smaller and 

 squarer. Along each side of the flat part already described, and 

 partly imbedded in it, but not reaching its anterior edge, runs a 

 raised, rounded portion, which is oval in Nothrus theleproctus, but 

 varies a little in different species. I have not ever succeeded in 



* " Ueber den Bau von TronMdium," Bull. Soc. des Nat. de Moscou, 1879. 

 t • Die Menschlichen Parasiten,' vol. i. 

 X Quart. Journ Micr. 6ci., 1880, p. 317. 



