614 THE ANIMAL KINGDOM. 



carries a larger pair of posterior limbs. The hypodermis is composed 

 of nucleated protoplasm. The nervous system consists of cerebral ganglia, 

 oesophageal commissures, and a pair of ventral cords which fuse in each 

 somite to form a ganglion. Organs of special sense are the sensory setae 

 of the cephalic tubercles, and of a similar tubercle attached to each 

 posterior limb. The digestive tract is ciliated and consists of an oeso- 

 phagus, stomach-intestine and short rectum. The mouth is ventral, the 

 anus terminal ; both are surrounded by cilia. The oesophageal bulb is 

 armed with three chitinoid jaws. The three first somites of the body 

 possess each a pair of ciliated nephridial tubes. A fourth pair occurs close 

 to the third in the female, but close to the ventral genital opening in 

 the male, which has also a fifth pair in the first of the three posterior 

 somites. The sexes are separate. Testes and ovaries are formed by the 

 growth of splanchnopleural coelomic epithelium. The genital ducts in 

 the female are a pair of wide ciliated tubes opening each into a dilatation 

 in which sperm has been observed, and this in its turn into a second 

 dilatation. The external apertures are lateral like the nephridial, and the 

 hypodermic cells surrounding them enlarged. The latter probably secrete 

 the egg-shell. The male appears to possess a pair of lateral evaginable 

 penes. A median ventral genital opening leads into a canal which bifur- 

 cates, each of its branches ending in a vesicle. Sperm has been observed 

 in these vesicles. Internal openings to the male ducts have not been 

 observed. Vascular system absent (?). 



Foettinger, Archives de Biol. v. 1884. 



% 



The family Polygordiidae includes the two genera Protodrilus and 

 Polygordius. The species of the former genus are of minute size, pro- 

 vided with a longitudinal ventral and ciliated furrow, a muscular sub- 

 oesophageal bulb, and are hermaphrodite. The best known is P. Leuc- 

 karti from Messina, which is about 4 mm., long. The segmentation 

 of the body is marked only by fine lines, by bands of cilia and internal 

 septa ; the last somite carries a pair of terminal glandular adhesive lobes. 

 The head has a pair of long tentacles or palpi. Cilia are found on the 

 tentacles, ventral aspect of the head, in the ventral groove, as a double 

 prae-oral band, and five simple post^oral cephalic bands, as well as two 

 bands, one at each end of every somite. The nervous system consists 

 of a cephalic mass, two oesophageal commissures, two ventral cords 

 connected from place to place by transverse fibrous commissures, 

 but separated by the ventral groove. A gradual transition between 

 ganglion cells and ordinary hypodermis cells is observable. The mouth 

 is ventral, the anus terminal. The digestive tract is ciliated, and consists 

 of oesophagus with sub-oesophageal bulb and intestine. There is a 

 dorsal and ventral blood-vessel. A contractile bulb developed on the 





