16 RECORDS OF THK AUSTRALIAN MOSKUM. 



resembling those present in certain species of Ichthyotasnia 

 (Proteocephalus)** and in some species of Diorchis' 60 (D. 

 acuminata, Clerc, and D. americaua, Ransom). The rostellum 

 when fully everted is a prominent organ of 0T03 mm. in 

 length, the width of the somewhat swollen extremity being 

 0-08 mm. Situated on this latter portion are the ten hooks 

 (about O068 mm. long) arranged in a single circle. As in 

 other members of the genus the dorsal root of the hook is 

 relatively long (0042 mm.), the ventral root being short ami 

 rounded. The claw is 0*025 mm. in length. The form of the 

 hook is seen in PI. ii., fig. 3. The rostellum may be so deeply 

 retracted that the hooks lie on a level with the lower part of the 

 suckers (PI. ii., fig. 2). Connected with this rostellum is a 

 strongly muscular rostellar sac whose inner limit lies behind the 

 level of the suckers. 



The scolex is succeeded by a short unsegmented neck of 

 variable length but whose breadth (0-14 mm.) is only slightly 

 less than that of the scolex. The first segments are very short 

 but they gradually increase both in length and width. In 

 proglottids in which male sexual maturity has been reached, the 

 sizes are 0T1 by 0*5 mm. With advancing female maturity the 

 segments become broader (0 - 90 mm.) and relatively shorter 

 (0096 mm.), whilst those which contain ripe eggs may measure 

 0T74 mm. in length by one mm. in breadth. 



Body-wall, etc. — The specimens are too poorly preserved to 

 allow of an examination of the subcuticular structures. Calcar- 

 eous corpuscles are very abundant. They are eliptical in form, 

 varying somewhat in size, their average being about 00078 by 

 •0045 mm. They are restricted to the outer layers of the cortex. 

 The lateral nerve is situated at about midway between the 

 excretory vessels and the margin of the segment, the genital 

 ducts passing over it. The parenchyma musculature is well- 

 developed, the longitudinal bundles being arranged in two series, 

 an outer ring consisting of numerous small bundles and an inner 

 series of eight large bundles (PI. ii., fig. 8), each consisting of a 

 number of very powerful fibres. The arrangement of the longi- 

 tudinal musculature seems to be typical in this genus. Trans- 

 versa fibres appear to l>«' very poorly developed. 



The excretory system consists of a larger ventral and a smaller 

 dorsal pair, the hitter lying above and sometimes slightly laterally 

 from the former. Both lie ventrally to the genital ducts on the 



» 8 Johnston— Joum. Roy. Soc. N. S. Wales, xliii., 1909, p. 103, etc. 

 so Kanso-n-Bull. U. S. Nat. Museum, 69, 1903, p. 42, etc. 



