4 Verm, 
VERMES. 
forms of the last, he has found a complicated system of fine canaliculi 
arising from small ciliated infundibula. The author now sees that 
secondary foramina may become developed, and that the terminal vesicle 
may disappear. Regarding a complete Cestode as equivalent to a Tre- 
matode, he looks upon the presence of secondary foramina as due to the 
development of the proglottids ; as they come more and more into use, 
the vesicle atrophies. He does not, however, regard the “segmental 
organs of a Cestode as comparable to those of an A.nnelid, but as the 
homologue of the head-kidney of Annelids, Gephyrea^ and Mollusca. 
His views on the body-cavity are criticised by E. Ray Lankester (Zool. 
Anz. iv. pp. 308-310), who points out that he had always believed, what 
Fraipont and Biitschli have demonstrated, that the ultimate ramifications 
of the canal system are comparable to a coelom ; see also E. von Beneden, 
Zool. Anz. iv. pp. 455-459, and Lankester, pp. 572-575. 
Van Beneden (1) describes the development of Tcenia serrata^ T. sagi- 
nata, and T. porosa ; the albuminigenous layer is regarded as being the 
final remnant of a primitive ciliated covering membrane ; and he raises the 
question whether the two layers of cells found in the hexacanth embryo 
are or are not homologous with the primitive layers of the Gastrula. 
M^gnin (21) finds that Tricuspidaria nodulosa may go through all its 
stages within the same host ; those without hooks found in the peri- 
tonaeum are the Ligula nodosa of earlier writers and the embryo (Ber- 
tolus) of Bothriocephalus latiis. He looks upon the scolex of some forms 
as being a transitory structure, and describes the life-history of Tcenia 
lanceolata^ T. infundihuUformis, and T. echinobothrida, sp. n. 
On the life-history of Bothriocephalus latus ; Braun (3). 
Moniez (22) discusses the development and the spermatozoa of the 
Cestodes ; Leuchartia : Ligula simplicissima ; Bothriocephalus latus ; 
Ahothrium gadi\ Schistocephalus dimorphus\ and the species of the 
type of Tcenia serrata. The author himself gives a summary of his con- 
clusions. 
The discovery by Villot of Cysticercus glomeridis, sp. n., (26) shows 
that the Arion-type is not, as Krabbe thought, confined to the 
Mollusca. 
Riehm (23, pp. 590-607) discusses the nature of the Cestoid individual, 
and upholds its monozoic nature. 
Thomas (25) has not yet succeeded in detecting the sporosac, or the 
Molluscan host, which contains it, of Distomum hepaticum ; he describes 
the characters and development of the embryo, and gives an account of 
his visits to, and his observations on infested pastures. 
Ercolani (see J. de TAnat. Phys. xvii pp. 434-436) finds that the same 
Cercaria, if developed in different animals, has different specific cha- 
racters ; see also H. A. Pagenstecher, Verb. Yer. Heidelberg (n.s.), iii. 
pp. 33-56, and C. Emery, Biol. Clblatt. i, pp. 104-106. 
Zaddach (27) is of opinion that in Distomum isostomum two sexually 
mature forms succeed one another ; the cysts of D. cirrigerum may be 
abundantly present in a crayfish without affecting its general health. 
Jourdan (10) details the Trematode characters of D. clavatum, which 
is remarkable for being at times free-living. 
