232 H. rrRAHAM CANNON 



8. The Rotae of the maxillae are directed anteriorl}'-, and by 

 their action pass the food on to the mandibles at the entrance 

 of the oesophagus. 



0. The labral glands stain very markedly intra vitara 

 with neutral red and Bismarck brown. There is no evidence 

 that this effect is due to the staining of the preformed structures 

 in the protoplasm. 



10. Females stained intra vitam with neutral red,, when 

 removed to fresh water will lay red eggs from which young 

 will hatch which are also stained. T'he stain disappears from 

 these during growth. 



1 1 . Agar's experiments on the transmission of an abnormality 

 produced by a certain food are criticized. This abnormality 

 can be produced by feeding Simocephalus vetulus 

 with Chlamydomonas. 



12. The secretion of the gland contains no mucin. 



EXPLANATION OF PLATES AND 10. 



Description or Figures. 



All figures are from Camera lucida drawings. Figs. 1-8 were 

 drawn using a Zeiss D. objective and are at a magnification 

 of 222 diameters. Figs. 9-12 were made with a Zeiss apochr(.- 

 matic N.A. 1.4, 2 mm. objective and compensating ocular 8. 

 The magnification is about 860. 



List of Abbreviations. 



a.l.g. external opening of duct of labral gland ; br, brain ; c.c. circum- 

 oesophageal commissure ; d.c. duct-cell ; d, duct of labral gland ; d.n. 

 dilatores oesophagi; ex. epidermal cell; f.g. food groove; gri 1, ganglion 

 of Antennarius 1 ; g.pg. group of nerve-cells in Antennarius 1 at root of 

 branch to proximal group ; I, labrum ; l.d.c. lumen of duct-cell ; l.g. lateral 

 groove dividing labrum from dorsal part of head ; l.l. labral nerve-loop ; 

 md, mandible ; mg, mid-gut ; nu; maxillae ; n.a. 1. Antennarius 1 ; n.a. 2'. 

 Antennarius 2 major ; n.a. 2". Antennarius 2 minor ; n.md. mandible 

 nerve ; n.mx. nerve to maxilla ; 7i.n.e. nerve to nauplius eye ; 7i.pg. nerve 

 to proximal group of gland-cells ; 7il, nucleolus ; nu.f.g. nucleus of proximal 



