8 



fourna] ol Entomolog\ and Zoologj 



reddish purple and the nucleus blue-black, rhese colls arc found 

 only in the front pari o\ the prostomium. Associated with these 

 in location are .1 number o\ mucous cells which have invaded the 

 brain and from their staining reactions seem to be functional i li^s. 

 5, 10; h). 



Cross-connective port oj the brain. The mam part oi the brain 

 contains the fibrilar cross-connections for the whole brain, I he 

 brain cells aw practicall) ail confined to the dorsal side. I he eyes, 

 tour iu number, are buried in this cell layer. The central pair is 

 ven small and vestigial, none oi the lense structure remaining and 

 but little of the pigment. I he lateral pair is complete, with lense 

 and cup-shaped pigment layer, but in all ol the specimens 1 have sec- 

 tioned the eye is inverted, with the pigment outside and the lense 

 facing Jown toward the bram. As it to render this ocular paradox 

 more striking the perfect eyes are deeply embedded in the head and 

 the degenerate eyes are just under the cuticle. This is a rather 

 interesting example ol degeneration. 



From the \\\\r o\ the brain extend the circumoesophageal com- 

 missure and the nuchal ganglia. The former is biramous, divid- 

 ing on each side into a dorsal and \ cntral branch. This is analagOUS 

 to the phenomenon found in Nepthys where the ocular And surface- 

 sensor) parts ot the brain are separate structures. (Quatrerages; 



I k) 



rhe nuchal ganglia (Figs. 13, I, 4; i), are connected to the brain 



b\ means o! two ner\cs .3 nun. apart, .03 mm. in diameter and 

 4 mm. long. These nerves come out from the "punkt-suhstan/" ol 

 the brain immediately below and behind the central pair ot eyes, 

 follow along the nuchal pits tor some distance, when they 10m on 

 the two nuchal ganglia ow their lower front surface. 1 he nuchal 

 pits act as a pair ot narrow -mouthed sacks opening, close together 

 lust under the lip ot the pcristomium, enlarging as the\ go in until 

 the) are large enough to contain in their thin ehitino-menibranous 

 sack, each, a ganglion. The apparatus bears a rather vague resem- 

 blance to the Otocyst found in Arcuicola [ Ehlers, '92) but inasmuch 

 as there are wo otolyths to be found and the onl\ cavit\ to contain 

 them is \ er\ small and pyramidal instead ot round, the diagnosis 

 is doubtful. The thing could hardly be functional, but is probably 



