246 J. T. CUNNINGHAM. 



is seen to pass obliquely backwards and downwards, curving 

 over the dorsal edge of the ventral longitudinal muscle, and 

 opening beneath the neuropodial bristles. The internal open- 

 ings of the simple nephridia are shown as seen in a horizontal 

 section in fig. 4, while fig. 5 shows the external opening in a 

 transverse section of a female specimen. 



The simple nephridia act as efferent ducts for the reproduc- 

 tive elements in both sexes. I found a number of specimens 

 distended with the genital products at the end of March in the 

 current year, lying under stones on the banks of Granton 

 Quarry, where they are pretty abundant at all seasons. These, 

 when placed in a basin of sea-water, commenced to shed eggs 

 and spermatozoa. The ova were fastened together, after their 

 escape, by transparent gelatinous mucus, which formed a soft 

 mass without any definite shape adhering to the stones and 

 mud among which the worms were lying. The escape of the 

 ova could be observed without much difficulty. 



Fig. 6 shows the appearance presented by two somites of the 

 worm viewed under a low power by reflected light, as the ova 

 were escaping ; the apertures seen are the openings of th e 

 simple nephridia previously described. In sections of a male 

 specimen these nephridia are seen full of spermatozoa. The 

 larger nephridia of the second somite do not, as far as I have 

 been able to ascertain, transmit the sexual products; indeed, 

 no ova (or spermatozoa) are produced in the first eleven 

 somites where simple nephridia are absent. 



I have not discovered in ray sections any satisfactory indica- 

 tion of the places where the germinal cells are developed ; the 

 position of the gonads is doubtful. The reproductive cells 

 undergo the greater part of their development in the body 

 cavity. The presence of a complete longitudinal vertical 

 septum above and below the intestine in Cirratulus is remark- 

 able. 



Spionid,e. — Nerine cirratulus, Clap. 

 This form has not hitherto been recorded as occurring in 

 the North Sea, either on our own coast or other parts of 



