PROCEEDINGS OF THE NATIONAL MUSEUM. 201 



to tlie inaccessibility of the publications aud the lack of details, Cur- 

 tice's observation lias not received much attention from helmin- 

 thologists. 



The only authors — so far as I can find — who have taken cog-nizance 

 of it are Neumann,' in 1S92, and Kailliet,-' in 1893, and Braun. Railliet 

 writes as follows: 



^n\)i-A\m\y Anoploceplialinir. * ^ * Tho life history is still unkuown. However 

 C. Curtice lias made an interesting observation on Lepns sijlvaticH», which will jiossi- 

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

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

 different stages of development. Some of them 5 nun. 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 AnoplocephaVmw is 

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

 development. (P'ree translation.) 



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

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

 r^hhit^ [L. Kylrai'u'us) n\ Maryland, and with this material the former 

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

 studied fresh, others nnnmted. 



Unarmed forms. — Nine of the mounted specimens showed no trace 

 of any rostellum or liooks, but on the other liand 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.bi-oadby 0.208 mm. long; constriction bai'k 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 mm. broad. 



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



4. 7 mm. 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 anlagen 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 bead. 



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, 0.24 mm. broad by 0.176 nun. long; segmentation, 0.224 

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



9. 0.6.56 mm. long; head, 0.24 mm. broad by 0.16 mm. long; suckers, 0.112 mm. in 

 diameter; segmentation begins 0.288 mm. back of head. 



Armc'l forms. — Twenty-seven mounted si)ecimens in which rostellum 

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



' Traitd des maladies parasitaires, 2d ed., ji. 461. 

 " Traitd de Zool. med. et agric, I, p. 268. 



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

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



