226 ON AUSTRALIAN ENTOZOA, 



seldom very distinct, the same may be said with regard to the 

 spines or hooks which in the greater number of specimens are 

 absent or cannot be observed. These tape-worms are numerous 

 in all the Australian Ducks examined, except in the Shoveller, in 

 the Musk Duck and the Pink-eyed Duck. Some of the intestines 

 are almost chocked with them. Smaller cestoid worms occur 

 from a quarter of an inch and less in length, all of which are imma- 

 ture specimens of the present, and probably of one or two other 

 species. 



On Plate III. will be found a sketch of these immature 

 bodies which are very difficult to secure in a perfect state, and 

 in most cases are destitute of the head ; I have succeeded, how- 

 ever, in getting a large number of them and will add the following 

 observations. The head generally resembles the matui'e heads of 

 No. 4 (Plate III.), or the half grown form No. 13, the proboscis 

 being rather large, and to use a popular expression " Top-heavy." 

 specimens resembling fig. 26a of the same plate occur, and 

 many like No. 27a are noticed, either with narrow and long, 

 or with broad and short joints. In the latter case the head 

 Las evidently been lost ; I have seen specimens, however, in 

 which the first joint appears quite perfect. It is of no value to 

 discuss every immature variety at present, I therefore draw 

 attention to fig. 25 of Plate III. which may be considered the type 

 of a young specimen of Taenia Bairdii, when from a quarter of an 

 inch to half an inch in length. Examples of from one-eighth of 

 an incli to less than a line in length occur in large numbers, all 

 inhabiting, in company with perfectly mature colonies, the same 

 host. 



The quantity of young, half grown and mature colonies from 

 a single ■ water-fowl host is quite astounding, yet all the birds 

 were in excellent condition, and did not appear to have suffered 

 from their guests. On a few occasions I have noticed lemnisci 

 thrust out in young specimens, but have not been able to preserve 

 them, and confess that even with perfectly mature ones this is a 

 rare occurrence. Among perhaps a thousand objects examined, 

 I did not find six with the lemnisci visible. The best specimen 

 is figured natural size, and enlarged on Plate III., figs. 7 and 7a. 



Kudolphi illustrates a similar cestoid worm (Entozoormn 



