50 SUMMARY OF CURRENT RESEARCHES RELATING TO 



former are connected by a transverse commissure, and each is connected 

 by a lateral band with the inferior mass, which is smaller in size as 

 compared with the other two. So far as the author was able to follow 

 the peripheral nerves from the inferior ganglia he found that they 

 took an ill-defined peripheral course, remaining distinct from one 

 another. Those from the supra-cesophageal ganglia took either an 

 anterior or a posterior direction. Those of the latter set go principally 

 to form the two lateral nerves, and they appear to send off branches 

 to the viscera. 



The author devotes a large part of his essay to an elaborate 

 account of the structure and arrangement of the very extensive genera- 

 tive organs, as to which we can only say here that in the genital sinus 

 the female orifice was found in the upper wall of the open end, and 

 the male pore at the base of the sinus. The double testes are anterior 

 or posterior, and are made up of a number of tubular glands. The 

 male efferent apparatus consists of paired, elongate eflfereni; ducts, 

 which open into the unpaired cirrus sheath. The ductus ejaculatorius 

 is provided with a number of appended glands. The female organs 

 are, primarily, the yolk-glands and the distinct germ-gland ; the latter 

 is a ramified tubular organ of much smaller size than it is in Tcenia. 

 The yolk-glands are placed in the lateral areas, and are the cause of 

 the opaque or reddish colour of those regions ; they, too, are compound 

 tubular glands. The protoplasm of their cells gives rise to yolk- 

 granules ; these, set free, pass into the efferent ducts, break up into 

 smaller parts and into a connecting substance, which latter unites the 

 former into the yolk-spheres. 



Monograph on the Cysticerci.* — M. E. Moniez, in his work on 

 this subject, after an historical review, gives an account of his own 

 researches. The first of these is on C. pisiformis (the " larva " of Tcenia 

 serrata), which is found in rabbits ; as to this he is in agreement 

 with Professor Leuckart in believing that the different larval forms of 

 Tcenice (the EcMnococci excepted) are developed on the same plan. 

 What does this cysticercal form represent ? At one time they were 

 believed to be hydropic parasites, but since the time of Kiichenmeister 

 it has been recognized that they form a normal and necessary 

 phase in the life-history of the Tcenice. It is an asexual condition. 

 Why is there exhibited the remarkable phenomenon of migration? 

 Leuckart believes that it is due to the modifications arising from the 

 fact that forms primitively confined to the non-vertebrated animals 

 become the guests of the more lately developed Vertebrata. In oppo- 

 sition to this view, M. Moniez submits the following considerations. 



The external parasites do not migrate ; all the endoparasitic forms 

 do. The reason is to be found in physiological and not in phylo- 

 genetic causes. The external parasite is submitted to a number of 

 variations in the circumambient medium ; the endoparasite lives a 

 life of continual uniformity. Variations are necessary to existence ; 

 the parasite in the digestive tube lives in conditions which threaten 



* Travaux Inst. Zool. Lille, iii. (1880) 190 pp. (3 pis.). See Journ. de 

 Microgr., iii. (1880) pp. 92-7. 



