275 MAF1NE 



ON A NEW TAPEWORM, DREPANIDOTAEN 



By T. B. Rosseter, F.R.M.S. 



(Bead January ldth, 1906.) 



Plate 20. 



This worm was taken, amongst other helminths, from the intes- 

 tine of a duck. Anas boschas dom., during the month of January, 

 1905. It was a perfect worm, having a mean length of 178 mm., 

 the mature proglottides having a breadth of 1*013 mm. and 

 length 0-338 mm. 



The scolex itself is pyriform, and perforated at its base with 

 a circular orifice. This orifice is not a depression caused by the 

 retraction of the rostellum inverting the cuticula of the base of 

 the scolex, but is a naturally formed inverted cavity from whose 

 sides spring the elastic muscles which elevate and retract the 

 rostellum. When the rostellum emerges from the cavity it is 

 a long, flexible -armed, attenuated organ, and, when fully exserted, 

 has a length of 0*051 mm. The hooks with which it is armed 

 are sickle-shaped, and are 0*010 mm. in length (Plate 20, Fig. 2). 

 Their number was not ascertainable, as caducity of the same had 

 set in ; and there was, and is in my preserved specimen, only 

 one hook left to enable me to determine the identity of the 

 species. 



At equal distances round the scolex are placed four oval 

 suckers (Fig. 1), the distal end of each sucker standing out from 

 the body of the scolex, so as to give it a barbed or arrow-headed 

 appearance. The scolex is 0*135 mm. long, and its approximate 

 diameter, including the suckers, is 0*203 mm. Strobilisation 

 commences at about 0*321 mm. from the scolex. 



The male genital pore is situated on the median lateral border 

 of the proglottis (Fig. 3). The vesicula seminalis, with its atten- 

 dant cirrus-pouch, curves strongly downwards, and then runs 

 upwards to the dorso- anterior border of the segment, its serpen- 

 tine vas-deferens ending in a moniliform spatulate testis. 



The testis (Fig. 3, d) is 0*106 mm. long, and its diameter is 



Journ. Q. M. C, Series II.— No. 58. 20 



