212 DR. W. B. BEISTHAM ON 



cases the copulatory organ is formed by an eversion of a mus- 

 cular sac carrying with it the pore of the sperm-duct which 

 traverses its wall, as again in Moniligaster *. 



I describe another species, P. malamaniensis with a penis 

 similar to that of P. Arturi. 



Amongst the slight variations in structure of this spermiducal 

 gland and apparatus in P. Arturi may be mentioned the fact 

 that, in one instance, the gland on one side was yqvj much 

 reduced. In another case it was three-lobed on one side (see 

 PL 16. fig. 4 S), and the penial duct passed below instead of 

 above the gland, possibly as the result of a sudden contraction or 

 struggle at the death of the worm. 



The worm may be characterized as follows : — 



Peeich^ta Aetttei, u. sp. 



Violet anteriorly, greyish brown posteriorly. Measures about 

 100 X 4 mm. (?), with 90 segments. Male pores slit-like, on 

 circular porophores ; a long thread-like penis protrudes from 

 each on peeling off the cuticle. One pair of spermathecse in 

 VIII., pore anterior ; globular sac, short duet ; diverticulum 

 longer than sac, slightly undulating, and scarcely dilated 

 terminally. Dorsal pore xi./xii. 



A dorsal gap interrupts the ring of chaet^, which are 50 before 

 and behind the clitellum ; those on iv. to Tin. larger. Simple, 

 paired intestinal caeca in xxvii. Spermiducal gland cleft into two 

 quadrate lobes, each much inclined ; penial duct long, between the 

 lobes, sharply bent in U-shape ; large glandulo-muscular sac with 

 a prolongation between the lobes of the gland, receiving the penial 

 duct. 



Hob. Blanche Bay, Grazelle Peninsula, New Britain. 



Affinities. — Of the four species of Periclicdta enumerated by 

 Beddard as showing a single pair of spermathecae in segment Tin., 

 none show any close resemblance to the present one ; though 

 P. sangirensis^ M., exhibits at first sight certain general 

 resemblances. A detailed comparison, however, readily distin- 

 guishes the two — in coloration and character of spermiducal 

 apparatus ; while the spermatheca has a well-marked duct into 

 which the diverticulum opens. In a few general features, too, 

 Bosa's P. atJieca bears a resemblance. 



* Bourne, Qu. Jour. Micr. Sci. sxxvi. pi. 28. fig. 65. 



