334 
SIDNEY F. HARMER. 
Fig. 17. — L. crassicauda. A nephridium, in the living condition, very 
highly magnified (Zeiss, Jj, No. 5 eye-piece). The adult from which the 
figure is taken was in the same relative position as that represented in Fig. 2, 
and the’nephrid ium corresponding to the right side of the figure was drawn ; 
the lower end of Fig. 17, containing the flame-cell {fl .) should lie on the 
ventral side of the stomach, the upper end ( ean .) opening into the vestibule, 
the median plane of the entire animal being situated to the left of the figure. 
Fig. 18. — L. crassicauda. Horizontal section of an adult, through the 
epistone ( epst .), the mouth (/».), and the bases of some of the tentacles (tf.). 
Only the basal portion of the bud ( b .) on the left side has been represented. 
Fig. 19. — L. crassicauda. Surface view of the foot-gland of a young 
bud, from a glycerine preparation. The constriction of the groove probably 
indicates the separation from one another of the “gland ” and the “duct.” 
Fig. 20. — L. Leptoclini. Transverse section through the middle region 
of the foot of an adult, al. Lateral expansions of the foot (cf. Fig. 2). 
fgd. The “ duct ” of the foot-gland, in reality an open groove. 
Fig. 21. — L. Leptoclini. Obliquely longitudinal section through the 
foot, passing through the “ gland ” ( fg .), but missing the “ duct.” 
Fig. 22. — Tendra zostericola, copied from Repiachoff (27), plate ii, fig- 
5 (a median longitudinal section of an embryo). Probable explanation of 
Repiachoff’s letters : — o. Mouth, v. Vestibular invagination (cf. fig. 39). 
g. Stomach, y. Sucker or foot-gland, e. hypoblastic cells taking part in 
the formation of the first bud. x. dorsal organ (?) 
Fig. 23. — Dentalium. Transverse section of a young individual (copied 
from Kowalevsky, No. 36 in the list of references, pi. viii, fig. 92). br. Brain. 
oe. oesophagus, me. Mantle cavity. /. Foot. 
Fig. 24. — Cyphonautes. An entire larva (slightly modified from Repia- 
choff, No. 27, plate i, fig. 1). Probable explanation of the lettering : — a. Vesti- 
bule. ce. (Esophagus, y. Sucker, g. Stomach (containing food particles). 
r. Rectum, zc. Dorsal organ (?). x. Epiblastic portion of young bud. 
e. Hypoblastic portion of the bud. 
PLATE XXI. 
With the exception of figs. 27 and 55, all the figures represent actual 
sections illustrating the embryology of Loxosoma. Figs. 25 — 59 belong to 
L. Leptoclini; Figs. 60 — 62 to L. Tethyae. The sections are all drawn 
to the same scale, with the exception of Figs. 54, and 56 — 59, which are more 
magnified. 
L. Leptoclini : 
Fig. 25. — Ovarian ovum. 
Fig. 26. — Two-cell stage. 
