ON PERICHAETIDAE. 205 



till five or six times that distance, and thereby the con- 

 tinuity of the series of large setae is also broken oS. In 

 the number of setae our worms agree very well with 

 Michaelsen's statement; I found on segment X 83 bristles, 

 while he mentions 81 on segment V and 90 on segment 

 X. The length of the enlarged setae is two and a half 

 to three times that of the ordinary ones; at their distal 

 extremity they are ornamented with obvious transverse 

 grooves. 



Similar variations in the number of spermathecae were 

 already observed by Beddard some years ago in a lot of 

 worms from Manilla belonging to P. posthuma^); besides 

 normal specimens with four pairs of spermathecae, he 

 found one individual with three pairs of them , another 

 one with no trace whatever of spermathecae , while in one 

 specimen there were in segment VIII on the right hand 

 three spermathecae in a row, instead of a single. 



Perichaeta Stelleri Mich. 



(P. Everetti Bedd., P. papillata Bedd., P. saraioacensis 

 Bedd., P. kinabaluensis Bedd.). 



In 1891 Michaelsen described a remarkable PericJiaeta- 

 species ^) from the Sangi-isles, distinguished by the fact that 

 it possesses numerous (16 — 28) spermathecae in segments VI 

 and VII , furnished with diverticula , which are swollen at 

 their base. The male pores situated on very prominent papillae 

 on segment XVIII; moreover a pair of copulatory papillae 

 on the three succeeding segments XIX — -XXL First dorsal 

 pore in the intersegmental groove XII/XIII. Setae in a 

 nearly continuous ring, on a prominent ridge; fifty-six in 

 the middle of the body. The 5th— 8th and 11th— 14th 

 septa specially thickened. Intestinal coeca absent. 



Four years afterwards Beddard described in his Mono- 

 graph of Oligochaeta, four new species from Borneo quite 

 allied to P. Stelleri: of those P. Everetti is also char- 



1) Ann. a. Mag. of Nat. History, Ser. 5, vol. XVII, 1886, p. 93. 



2) Jahrb. Hamb. Wissensch. Anstalten, VIII, p. 39. 



Notes from, the Leyden IVIuseura , Vol. X.X.. 



