114 T. H. JOHNSTON AND J. B. CLELAND. 



usually met with, reaching 7*4 mm., but its maximum width 

 is only 0*93 mm. In this specimen the cuticle is quite 

 smooth. There is a gradual tapering towards each end, 

 the posterior end being rounded off, while the anterior 

 terminates in the prominent rostellum. The latter is 

 0*74 mm. in length (measuring the whole eversible portion), 

 and 0*55 mm. in width. The hook-bearing part is practically 

 spherical, a somewhat narrower neck succeeding it. The 

 hooks appear to be arranged in eight transverse rows, there 

 being about forty altogether. Those situated anteriorly 

 are much more powerful than those located further back. 

 Each is surrounded by a kind of collar which projects 

 prominently around the basal region. These hooks, which 

 may reach 0'205 mm. in length, bear a marked resemblance 

 in general shape to those of the large Taeniae. The dorsal 

 root is short but thick and rounded, the ventral root being 

 relatively massive. The claw or blade which is the only 

 portion seen in ordinary preparations, is also prominent. 

 On its inner side near the tip, there is a distinct notch or 

 barb which no doubt adds considerably to the adhesive 

 power of the hook. 



The type slide of Echinorhynchus pomatostomi (from 

 Pomatostomus super ciliosus) will be deposited in the 

 Australian Museum, Sydney. 



Explanation of Figure. 



Echinorhynchus pomatostomi. 



Fig. 1. Usual form with rostellum retracted, from Pomatostomus 

 frivolus. 



Fig. 2. Specimen with rostellum protracted, from P. rubeculus. 



Fig. 3. Hook from rostellum, from P. rubeculus. 



Fig. 4. Portions of hooks from (a) Anterior series ; (b) middle 

 series ; (c) posterior series, drawn to same scale — 

 showing collar — from P. super ciliosus. 



Addendum. — In May, 1911, one of us obtained further speci- 

 mens of this parasite in Pachycephala gilberti, obtained near 

 Blanchetown in South Australia. Pomatostomus was in the 

 neighbourhood. 



