"W. R. Coe — Anatomy of Cerehratulus lacteus. 513 



Figure 9. — Sagittal section through a portion of the intestinal region of a male speci- 

 men with ripe spermatozoa. The genital products have developed between the 

 double bands of dorso-ventral muscles {dyri) and tilled up most of the space occupied 

 by the gelatinous tissue {gd^ fig. 8). In this section the spermatozoa are develop- 

 iag from the germinal cells (sc) above and below the intestinal caeca {ic). These 

 caeca are much flattened and the space between them is filled with ripe sperma- 

 tozoa (sp) ; av, anastomosing vessels ; Zm, internal longitudinal muscular layer of 

 the body- wall ; x 20. 



Figure 10. — Part of a median horizontal section through the intestinal region of a 

 specimen in which the genital products are just beginning to develop ; «, intestinal 

 canal ; «c, intestinal caeca, one of which is bilobed ; av, anastomosing vessel ; /, 

 split between intestinal caecum and gelatinous tissue ; ?e, columnar cells of intesti- 

 nal epithelium; dm^ dorso-ventral muscles in two thin, vertical bands which unite 

 near the intestinal canal ; gs^ genital sac in which the ova are just beginning to 

 develop; x 20. 



Figure 11. — Horizontal section through the intestinal region, of a female specimen in 

 which the ova are nearly ready to be discharged; ^■, intestinal canal opening into 

 the caecum {ic) ; gs^ enlarged genital sac filled with nearly ripe ova {pv). The 

 genital sac lies between the two bands of dorso-ventral muscles {dm)] x 20. 



Plate XV. 



Figure 1. — Part of a transverse section through the integument in the oesophagal 

 region ; e, ciliated and gland-cells of epithelium ; % interstitial cells among the bases 

 of same : &m, underlying basement membrane ; e??i, epithelial musculature con- 

 sisting of an outer circular and an inner longitudinal layer; Zm, longitudinal 

 muscles of cutis ; r/, radial nerve and connective tissue fibres, the latter forming a 

 framework for the tubular glands {tg) which discharge their contents to the 

 exterior among the epithelial cells ; c, connective tissue occurring abundantly in 

 the lower portions of the cutis; x 150. 



Figure 2. — Macerated cells from the body-epithelium. The cilia {ci) of the ciliated cells 

 (ce) are somewhat thickened near their bases. There are two varieties of gland- 

 cells : ^, cells which secrete a homogeneous, semi-solid substance ; and g', those 

 which have a coarse, granular, and deep-staining secretion; x 300. 



Figure 3. — Transverse section of the brain just back of the ventral commissure. The 

 fibrous core (/c) of the dorsal lobe is surrounded above and at the sides by gan- 

 glion-cells of the first type {gc'\ with scattered cells, of the third tj^pe {gc^) peripher- 

 ally. The fibrous core of the ventral lobe {jc') is provided with cells of the second 

 type as well as with those of the third type ; c, masses of connective tissue ; 

 cs^ inner sheath of connective tissue surrounding the fibrous cores : cs\ outer sheath 

 of connective tissue enclosing the whole brain ; x 40. 



Figure 4. — Body-epithelium in Micrura affinis ; g, gland cells among the ciliated cells; 

 X 125. 



Figure 5. — Transverse section through the posterior portion of the oesophagal region 

 of Carinella pellucida. The nephridial canal {u) lies near the large lateral blood- 

 vessel {Iv) ; that of the left hand side is seen to open to the exterior. The lateral 

 cords {Ic) are situated immediately beneath the thickened integument (c) and out- 

 side the outer circular muscular layer {cm') ; c??2, inner circular layer ; Im^ longi- 

 tudinal muscular layer ; X 50. 



