IS Verm. 
VERMES. 
G2. [Giard, a.] Nouvellee remarques sur les Orthonectula. C. R. Ixxxix. 
pp. 1046-1049. 
63. Metsciinikoff, E. Zur Naturgeschichte der Orthonectiden. Zool. 
Anz. ii. pp. 547-549. 
64. . Nachtragliche Bemerkungen. Tom. cit. pp. 618-620. 
Giard (61) gives a more detailed account of the Orthonectula [cf. Zool. 
Bcc. xiv. Verm. p. 20] ; ho defines them as Metazoa which retain through- 
out life the Planula-form, with a ciliated ectoderm, a tuft of stiff hairs 
in the anterior region, and an external metameric segmentation. 
Reproduction is effected by the gemmation of sporocysts developed from 
the endoderm, or oviparously, the sexual elements being probably in dis- 
tinct individuals. The genus Ilhopalura has a papilliferous ring, an 
ectoderm formed of large colls, and a distinctly muscular endoderm. R. 
ojahiocomce, 108 mm. long. Macintoshia llntoshia, G.] has no papilli- 
ferous ring, and an ectoderm formed of a large number of small cells. 
I. gigas (in Ophiocoma neglecta), I. linei (in Linens gesserensis), and I. 
leptoplance (in Leptoplana tremellaris). 
The Orthonectula arc degraded by parasitism, and stand in the phylum 
above the Gastrmda, and below the Dicycnida, Gasterotricha, and 
Protohelmintha. 
Metsciinikoff (64) believes that R. ophiocomce and I. gigas, Giard, are 
series of the same species, and that his own R. giardi (63), found in 
Amphiura squamata, is identical with them ; the smaller form is regarded 
as the male, and the so-called muscular elements as the tails of sper- 
matozoa. This and other criticisms are dealt with by Giard (62). 
