NO. 1105. PROCEEDINGS OF TIJE NATIONAL MUSEUM. 201 



to the inaccessibility of the publications and the lack of details, Cur- 

 tice's observation has not received much attention from helmiu- 

 thologists. 



The only authors so far as I can find who have taken cognizance 

 of it are Neumann, 1 in 1892, and Kailliet, 2 in 1893, and Braun. Railliet 

 writes as follows : 



Subfamily Anoploceplialinw. * * * The life history is still unknown. However 

 C. Curtice lias made an interesting observation on Lepua sylvaticu* t which will possi- 

 bly place experimenters in a position to determine the development. He found in 

 the intestine a large number of small Twniadw which were still very young, but in 

 different stages of development. Some of them 5 mm. long, nonsegmented, pos- 

 sessed between the suckers a dome-shaped depression, bordered with 85 to 90 hooks; 

 others, still older, had lost their hooks, while some did not even show the cor- 

 responding depression ; finally, some of them were segmented, but all of these were 

 unarmed. One is thus led to suppose that the larval stage of the Anoplocephalinw is 

 represented by an armed cysticercoid and that the hooks disappear during the 

 development. (Free translation.) 



Curtice's observation I confirmed and extended in 1894. 3 Since pub- 

 lishing this note, Hassall has found the same young stages in several 

 rabbits (L. sylvaticus] in Maryland, and with this material the former 

 description can be amplified. Of the young forms collected some were 

 studied fresh, others mounted. 



Unarmed forms. Nine of the mounted specimens showed no trace 

 of any rostellum or hooks, but on the other hand some of them exhib- 

 ited traces of segmentation. The details of measurements, etc.. are as 

 follows : 



1. 0.544 mm. long; head, 0.24 mm. broad by 0.208 mm. long; constriction back of 

 suckers 0.128 mm. broad; suckers, 0.112 mm. in diameter. 



2. 0.848 mm. long; head, 0.256 mm. broad by 0. 192 mm. long ; constriction back of 

 head, 0.12 rum. broad. 



3. 0.304 mm. long; head, 0.208 mm. by 0.208 mm. 



4. 7 nun. long; head, 0.448 mm. broad by 0.32 mm. long; suckers, 0.196 mm. diame- 

 ter; constriction back of head, 0.368 mm. broad. The transverse lines of the seg- 

 mentation become indistinctly visible almost immediately back of the head, but no 

 genital anlageu are seen in any portion of the specimen. 



5. 0.816 mm. long; head, 0.256 mm. broad by 0.24 mm. long; signs of segmentation. 



6. 0.64 mm. long; head, 0.224 mm. broad by 0.176 mm. long; suckers, 0.112 mm. in 

 diameter; segmentation begins 0.224 mm. back of the head. 



7. 0.816 mm. long; head, 0.24 mm. broad by 0.192 mm. long; segmentation percep- 

 tible, 0.4 mm. back of head. 



8. 0.64 mm. long; head, 0.24mm. broad by 0.176mm. long; segmentation, 0.224 

 mm. back of head; suckers, 0.144 mm. in diameter. 



9. 0.656 mm. long; head, 0.24 mm. broad by 0.16 rnm.long; suckers, 0.112 mm. in 

 diameter; segmentation begins 0.288 mm. back of head. 



Armed forms. Twenty-seven mounted specimens in which rostellum 

 and hooks were present varied in measurements as follows: Length, 



1 Traite" des maladies parasitaires, 2d ed., p. 461. 



2 Trait6 de Zool. med. et agric., I, p. 268. 



3 Notes sur les Parasites 31 : Une phase precoce du tenias du Lapin, Bull. Soc. 

 zool. France, XIX, pp. 163-165. 



