100 
Fig. 
Fig. 
Fig. 
Fig. 
Fig. 
Fig. 
Fig. 
Fig. 
TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. 
Le 
vo 
Prats LY. 
Longitudinal section of a single ommatidium. 
(Drawn with the camera lucida.) — (ace. con.) 
accessory cone; (b.m.) basement membrane; 
(con.) cone; (corn. cut.) corneal cuticula; (nue. 
con.) nucleus of cone cell; (nue. ret.) nucleus of 
the retinular cell; (op. n. f) optic nerve fibre ; 
(pg.) pigment; (pg. ¢.) ae cell; (ret.) 
retinular cell; (rh.) rhabdomere; (s-c. hyp.) 
sub-corneal hypodermal cell. 
Transverse section of ommatidium showing the 
six retinulae cells and their rhabdomeres. 
Longitudinal section through the cuticle of a 
segment of the flagella of “the second pair of 
antennae to show a sensory bristle and its 
nerve supply. (ch.) thick layer of chitin; 
(ctla.) cuticula; (hyp.) hypodermal layer; (n.f.) 
nerve fibrils ; (s.b.) sensory bristle; (sh.) sheath 
of sensory bristle. 
Generative organs of the male. (t.) testes; 
opening into (v.d.) the vas deferens, which 
opens externally by the styliform appendages 
(st. ap.). 
A collection of ‘sperm-colonies’ as they are 
found in the vas deferens, in the cohesive 
substance secreted by the latter. 
Early stage in the development of the egg, 
showing the cleavage of the germ disc into the 
two antero-lateral mesoderm fundaments (a.m.) 
and the median posterior endoderm fundament 
(end.). 
The ‘nauplius’ stage of the development of 
Liga, showing the three naupliar appendages. 
(1.a.) and (2.a.) the first and second pairs of 
antennae, and the mandibles (mand.); (end.) 
endoderm fundament; (f.z.) formative zone; 
(op.) optic lobe. 
A later stage in the development, showing the 
elongation of the formative and the formation 
of appendages, also the rudiments of the 
gangha. (an.) anus; (1. and 2. ma.) first and 
second pairs of maxillae; (map.) maxillipedes. 
The last three figures are after Nusbaum. 
