16 Verm. 
VERMES. 
is shown to be narrow anteriorly, and to be divided posteriorly by a 
median ligament ; the appendages of the ninth segment are very peculiar, 
and are shown to be homologous with similar appendages on other seg- 
ments in other Annelids; the integument presents a high degree of 
development in its anterior region, and the hypodermis is exceedingly 
well developed ; the anterior region of the enteron is regarded as having 
a close homology to the oesophagus of the Nemertinea. 
The researches of Whitman (58) lead to the following conclusions : the 
ovarian cord consists of a central portion, which is homologous with the 
rachis of the Nematodes^ and which consists of nucleated protoplasm, 
whence arise the primitive ovarian cells, and a peripheral portion; the 
germinal vesicle gives rise to two “ directive vesicles ” and the female 
pronucleus, which unites with that of the male to form the first cleavage 
nucleus ; it contains two nucleoli. The larger of the first two cleavage- 
spheres contains a large part of the ectoderm, the whole of the mesoderm, 
and about a third of the endoderm ; the inferior pole of the largest of 
the first four blastomeres is converted into two mesoblasts, and the 
superior pole into eight neuroblasts ; from these two sets of cells the 
germinal stripes are produced. The ectoderm is developed from the 
superior pole of the ovum ; the endoderm, which arises from free nuclei, 
encloses the deutoplasm ; the mouth, anus, and pharyngeal atrium are 
formed by the invagination of the ectoderm ; the ganglionic chain is 
formed of 8 neuroblasts ; the testes appear to be formed from a single 
pair of cells in each metamere ; and, finally, the circulatory system con- 
sists of a closed vascular, and of a lacunar system. 
V. Mojsisovics (50 a) points out the presence of two distinct forms of 
glands in the clitellum, and notes the presence of gustatory organs in the 
praestomium. 
Hertwig continues his essay on the earlier characters of the egg. Deal- 
ing with those of the Vermes (Morph. JB. iv. p. 188), he points out that 
in Sagitta there are a number of smaller nucleoli in the place of one 
germinal spot, and that the germinal vesicle disappears. There are also 
a few words on the ova of A Iciope. 
R. Blanchard gives an account of the process of fecundation in Annu- 
lata ; J. de I’Anat. Phys. 1878, pp. 710-717. 
Semper (54) deals with some of the statements made by Furbringer in 
his essay on the excretory organs of the Vertebrata (Morph. JB. iv. 
p. 1) ; Furbringer retorts (tom. cit. pp. 663-679). 
Fredericq (Bull. Ac. Belg. 2, xlvii. No. 8) gives an account of the 
digestive ferment of Lumbricus terrestris (pp. 217-220), Nereis pelagica 
(p. 220), Hcemopis vorax (p. 221) ; also in Arch. Z. exp4r. vii. 3, pp. 
394-396. 
Krukenberg’s researches (Unters. physiol. Inst. Heidelb. ii. p. 3) are 
reviewed in Arch. Z. expdr. vii. 3, pp. xxxi. & xxxii. ; the ferment in Vermes 
(isothrypsin) is not identical with that of Vertebrata ; in Aphrodite 
aculeata the digestive secretion is formed in glandular cells of the hepatic 
follicles. 
Lankester (45) describes the blood corpuscles of the Earthworm as 
flattened, fusiform, colourless bodies, the majority ^oVo i^ich in long dia- 
