DR. T. S. COBBOLD'S SYNOPSIS OV THE DISTOMID.'E. O 



Genus 3. Distoma, Zeder. 

 This genus, even in its reduced limits, embraces a very large pro- 

 portion of the digenetic Trematodes ; and its members are charac- 

 terized chiefly by their varied form and size. The presence or 

 absence, either in whole or in part, of dermal spines, forms in some 

 instances a distinguishing feature ; but this character has not been 

 recorded with sufficient accuracy. Much uncertainty exists in 

 regard to certain of the species, which are probably larval forms, 

 and also in respect of others that have not been figured or have 

 only been imperfectly represented. The presence and condition 

 of the reproductive organs are the best criteria of the adult state. 



A. In corpore mammalium. 



1. Distoma lanceolatu.ai, Mehlis. 



Distoma lanceolatum, 3Iehlis, Observ. de Dist. hep. et lanceolat., 1825, 

 with figs. ; also Guilt, Valentin, Dnjardin, Blauchard, Diesing, Baiid, 

 Kiichenmeister, Leid}-, Moulinie, Dubiiii, and others. 



D. hepaticum, Zeder, Rudolphi, Bremser, Olfers, Bojanus, Creplin, 

 Gurlt, Owen (Art. Entoz.) 



Fasciola liepatica, Bloch, Jordens, Bosc. 



F. lanceolata, Rudolphi. 



Planaria latiuscula, Goeze. 



Hab. Usuall)^ occupies the gall-bladder and biliary ducts of the liver, 

 and sometimes, accidentally, the intestine of domesticated ruminants. 

 It has been found or noticed in Cervus Elephas hy Rudolphi, in C. 

 Dama by Schaeffer, in Lepus Cuniculus by Bremser, in L. timidus by 

 Zeder, by Goeze in the Stag. Bucholz records an instance of its pre- 

 sence in the human subject; and another case (about which, however, 

 there is some doubt) is noticed by Chabert and Mehlis. 



The last-named authority was the first to draw attention to the non- 

 identity of this and the common fluke, and, but for the circumstance 

 of these animals being so frequently found in the same host, the spe- 

 cific difterences could not have been so long overlooked. 



2. Distoma crassum (Cobbold). — Corpus planum, oblongum, utrin- 

 que obtusatum, inarmatum. Os termiuale, orbiculare. Acetuhulum 

 ore majus, superum ad colli basin, apertura circular!. Longit. 3-.'ti 

 line. ; latit. |-f unc. 



D. Buskii, Lankester (non ilescrlptum) ; in A[)pendix B to his transla- 

 tion of the 2nd edit, of Kiiclienmeistcr's ' Parasiten,' p. 437- 



Hab. At the suggestion of the original discoverer, I have applied the 

 above title to this interesting species. Fourteen si)eciincns of this 

 worm were found by Professor Busk in the duodenum of a Lascar in 

 1843, and it is worthy of remnrk that there were no e.xamjiles either 

 in the gall-bladder or biliiiry ducts. Although undescribed hitherto, 



