DESCRIPTIONS OF GENERA AND SPECIES . 425 



with a zigzag diverticulum and one or two eopulatory glands opening into long duet 

 of spermatheca. Spermiducal glands extend through XVI-XXII. Hah. — India ; Cochin 

 China; Philippines ; Bahamas. 



This species is one of the few that has been investigated by a considerable number 

 of observers. Pebbiee (3), Hoest (17), Rosa (9), Bouene (3), and I (62), have 

 combined to collect a considerable number of details about the anatomy of P. houUeti. 

 Our knowledge of the species appears to me to show that Hoest is perfectly right in 

 declining to recognize Rosa's species, P. campanulata as valid; the differences upon 

 which Rosa relied are the shape of the gizzard and the dilated oesophagus which 

 precedes it; these points, however, are simply corrections by Rosa of the more 

 inaccurate descriptions of his predecessors. The most obvious character by which 

 this species can be distinguished is, of course, the unique form of the clitellar setae. 

 Pebbiee gave a more detailed account of this species than of any other, and his 

 paper, as well as the others quoted, contains figures of all the important anatomical 

 characters. I have dealt in many places in the present work with these characters 

 (see index), and, therefore, need not now give any further account of the species. 



I have occasionally observed an irregularity in the setae, the line of their 

 implantation being not perfectly straight. 



I very much doubt whether P. udekemi of Michaelsen from Java is really 

 different. 



(55) Perichaeta musica, Hoest. 



Megascolex musious, HoEST, Notes Leyd. Mus., v, 1883, p. 193. 

 P. musioa, Hoest, ibid., xii, 1890, p. 336. 



Defimtion. Length, 570 num.; number of segments, 66. Clitellum without setae. Male 

 pores on a line with sixteenth seta. Setae, 100 to each segment; a very small dorsal 

 gap. Dorsal pores commence XII/XIII. Intestine often with six caeca. Septa X/XIII, 

 thicTcened. Spermathecae in VII, VIII, each with a long coiled diverticulum longer 

 than pouch. Hah. — Java. 



This, the largest species of Perichaeta and one of the largest of earthworms, has 

 been figured by Voedebman. Its colour when alive is greyish blue above, rufous 

 below; the clitellum is brownish. It is stated to produce a sound during the 

 night, probably caused by the setae coming into contact with pebbles. It is the only 

 species not Japanese which has six caeca on the intestine, but this character is not 

 always met with. 



31 



