SEA-FISHERIES LABORATORY. 275 



not over the whole of each oval area as in the adult. Very 

 fine debris is present in the intestine of one or two speci- 

 mens, but in most the gut is practically empty. 



The blood-vessels are well developed, and are 

 arranged as in the adult. The blood is reddish or pink 

 in colour. The heart is a simple tube, dilated at its upper 

 end, and contracting frequently. The two hearts do not 

 beat in unison. The wall of the ventral vessel contains 

 numerous spherical yellowish (some nearly colourless) 

 granules, probably chlorogogenous. The flow of blood in 

 the dorsal vessel is from behind forwards. 



Cells are already abundant in the coelomic fluid. 

 They are mostly oval, or spindle-shaped, and about "02 mm. 

 long. Many of them, especially the oval cells, already 

 contain yellow granules. 



The musculature is similar to that of the adult. 

 Longitudinal muscles are well developed, the circular 

 ones only feebly so, and the oblique muscles are very 

 slender. 



There are six pairs of nephridia opening near the 

 fourth to the ninth neuropodia, as in the adult. Each 

 nephridium is a curved ciliated tube (fig. 31), the 

 lips at the anterior end of which are slightly everted, and 

 one is larger than the other. Attached to the larger lip 

 and hanging over towards the smaller are (except in the 

 first nephridium) from four to eight protoplasmic pro- 

 cesses* which are only visible in living specimens (fig. 32). 

 They are generally of unequal length and in the living 

 specimen, 4"6 mm. long, the longest processes measured 

 only - 03 mm. Each process is slightly swollen about the 

 middle of its length and tapers distally. It bears about 

 ten moderately strong, long cilia directed backwards 



* See Goodrich, Quart. Journ. Micr. Science, p. 729-730, fig. 49, 

 Vol. 43, 1900. In his specimen the processes appear to have been 

 rather longer than in mine. 



