232 The American Naturalist. [March, 



fers, however, in his interpretation of these organisms from the views 

 advanced by Wright and arte; wards accepted by hem-hart, in that he 

 considers that we have in this case not a sporocyst stage but a cercaria 

 stage, in which the anterior portion of the body (the Dutomd) hat 

 crawled into its own tail, He has given the name Cercaria mirabids to 

 the larva, but is as yet unable to tell to what species of Distoma it 

 belongs. Prof. Braun's view seems to be the correct one, as he exam- 

 ined the organism in various stages of development. 



Dr. Raphael Blanchard, " Histoire Zoologique et Medicale des Ten- 

 iades du genre Hymenolepis (Weinlandj." Prof. B. begins with a for- 

 mer review of works on this genus, dwelling at some length on Grassi's 

 experiments, in which the latter showed that H. murina has an indi- 

 rect development without change of host. 



The embryo enters the villosities of the intestines, where it develops 

 into a cercocystis, which afterwards becomes free in the lumen and 

 develops into the adult tape-worm. This is the only case where it has 

 been demonstrated that a Taenia can pass its full development without 

 change of host. 



Blanchard's diagnosis of the genus Ilvmenolepis is as follows: 

 Body small, filiform; head small, provided with a retractile rostel- 

 lum — well developed and armed with a simple crown of 24-30 minute 

 hooks or rudimentary and unarmed; neck long; segments serrated, 

 much wider than long, in number rarely less than 150. Sexual pores 

 marginal, piercing the left border, the ventral face being that which is 

 occupied by the female genital organs. The male genital apparatus 

 contains a very small number of testes, generally but three, two of 

 which lie in the right half of the segment, the third in the left half. 

 Mature segments transformed into a sack full of round or oblongated 

 clear eggs ; there are three concentric yet separated egg shells. The 

 internal shell contains the oncosphere (six hooked embryo), pos es-es 

 no pyriform apparatus, but sometimes shows a papilla at each pole. 

 The larvae is either a cryptocystis (cercocystis) or a staph} cv-tis. 

 Development is indirect, either without change of host, but with a 

 migration from one organ to another, or more frequently with change 

 of host, the intermediate host being an insect or mvriapod. 



A list is then given of all the know species (14 according to Blan- 

 chard), their hosts, intermediate hosts and larval forms, so far as 

 known. Blanchard is not readv to accent ( Ira-si's view that ILpnirina 

 of the rat and H. nana of man are identical. 



The latter half of the hook is given up to the more pun h medual 

 side of the question. Diagnosis, symptom-, treatment, etc. 



