12 Venn» 
VERMES. 
56. Lankester, E. R. Observations on the Microscopic Anatomy of 
the Medicinal Leech {Hirudo medicinaliH). Zooh Anz. iii. pp. 85-90. 
57. . On Intra-epithelial capillaries in the Integument of the 
Medicinal Leech. Q. J. Micr. Sci. xx. pp. 303-306, pi. xxvi. 
58. . On the Connective and Vasifactive Tissues of the Medicinal 
Leech. Tom. cit. pp. 307-317, pis. xxvii. & xxviii. 
59. Leidy, J. Notice of some Aquatic Worms of the Family Naiades. 
Am. Nat. xiv. pp. 421-425. 
60. Panceri, P. La luce e gli organi luminosi di alcuni Annelidi. 
Atti Ac. Nap. vii. [1878] art. i. pp. 20, pis. i.-iv. 
61. Schneider, A. Ueber die Auflosung der Eier und Spermatozoen in 
den Geschlechtsorganen [^Nephelis, Aidostomum, Hirudo']. Zool. Anz. 
iii. pp. 19-21, 256 & 257. 
62. Weyenbergh, H. Descripciones de nuevos gusanos. Period. Zool. 
Argent, iii. pp. 106-111, and Bol. Ac. Arg. iii. [1879] pp . 213-219. 
63* . Algunes nuevas sanguijuelas o chaucacas de la familia 
Gnathobdellia y Revista de esta familia. Tom. cit. iii. pp. 112-125 ; 
and tom. cit. pp. 231-245. 
64. Wilson, E. B. Early Stages of some Polychietous Annelids. Am. 
J. Sci. (3) XX. pp. 291 & 292 ; see also Zool. Anz. iii. pp. 455 & 456, 
and Ann. N. H. (5) vi. pp. 407 & 408. 
Anatomy, Development, &c. 
Hatschek’s new genus (52) appears to exhibit even greater simplicity 
than Polygordius ; there is no external segmentation, and locomotion is 
largely effected by means of cilia. The hindermost segments are but 
imperfectly differentiated ; a thickening of the integument is the only 
indication of the frontal ganglion ; the ovaries are developed in the more 
anterior and the testes in the more posterior segments. 
Blomfield’s observations (48) result in a careful account of the true 
testes of the earthworm, an account of the minute structure of the 
seminal vesicles, and a history of the development of the spermatozoa ; 
the ‘ spermatospores ’ by division of their nuclei give rise to ‘ spermato- 
pheres,’ each of which is made up of spermatoblasts ; these become deve- 
loped into spermatozoa. \_Ocnerodrilus (Eisen) has throughout life simple 
testes ; cf. J. R. Micr. Soc. (2) i. p. 44.] 
Cosmovici (50) has especially studied Arenicola piscatorum and Tere- 
bella g\gantea\ comparisons are made with members of several other 
families. 
On the epithelial investment of the otocyst in Annelids, see Chatin, 
Bull. Soc. Philom. (7) iv. pp. 130-132 ; on sub-intestinal system, pp. 
81-83. 
Lankester (56-58) and Bourne (49) have added considerably to our 
knowledge of the minute structure of the Leech ; the latter points out 
