62 SUMMARY OF CURRENT RESEARCHES RELATING TO 
Polydora.* * * § — M. F. Mesnil contributes an account of his study of 
some of the species of this Annelid. P. cseca appears to be the most 
primitive, while P. ciliata is much more differentiated ; Pygospis elegans 
has a number of the characteristics of Polydora , and Spio Mecznikowianus 
has a close relation to the same type. P. Giardi sp. n. has been taken 
at Wimereux (Pas-de-Calais). 
New Irish Earth worms, f — The Rev. H. Friend describes two new 
species of Earthworms found in Ireland, which he calls Lumbricus papil - 
losus and Allurus macrurus. It is remarked that the habitat of an earth- 
worm is related to the shape of its hinder end. It is only the species 
which expose a portion of their body when in search of food, while the 
other remains in the burrow, that have a distinctly flattened tail. 
Jaws of Hirudinea.f — Herr J. M. Croockewit finds that the number 
of unicellular glands in the head of Aulastomum are much less numerous 
than in Hirudo ; their secretion contains a large number of small granules, 
which stain deeply with haematoxylin ; by their means the glands and 
efferent ducts can be easily made out. The teeth, which are completely 
enclosed in the cuticle, may be isolated by caustic potash ; or, for 
purposes of sections, they may be decalcified in picric acid and alcohol. 
In sections it may be seen that the cuticle which invests the epithe- 
lium of the jaw, increases greatly in thickness on the anterior and 
hinder surface of the jaw, as soon as it reaches the free edge. Between 
the cuticle of the anterior and that of the hinder surface there is a cleft- 
like space ; in this the efferent ducts open, but, wherever there is a tooth, 
the space is closed. The decalcified teeth stain well with haematoxylin, 
but the cuticle remains free from it ; the tips of the teeth do not project 
beyond the free edge of the cuticle. 
The teeth may be considered as the supporting apparatus of the cut- 
ting cuticle ; as soon as the wound is made by the jaws it is impregnated 
with the secretion which pours out between the teeth, and the coagula- 
tion of the blood is thus prevented ; for, as Haycraft has shown, there is 
in the head of Hirudo a substance, which delays the coagulation of the 
blood. Further details are promised. 
Infundibular Apparatus of Hirudinea.§ — Prof. R. Leuckart cor- 
rects what he takes to be some errors in the descriptions given by pre- 
ceding writers on the nephridia of Leeches. He finds that the masses of 
granular structures which Bourne regarded as degenerative are cells 
which, but for their size, closely resemble typical nephridial cells. The 
spaces amongst them, whether canalicular or lacunar, are all in direct 
connection with the canal system of the nephridia. The author gives a 
short sketch of the differences exhibited by various genera of Hirudinea. 
Eye of Clepsine.|| — Prof. C. 0. Whitman criticizes severely some 
conclusions reached by B. L. Maier If in regard to the eye of Clepsine. 
“ A theory of the development is put forward without so much as a 
* Comptes Rendus, cxvii. (1893) pp. 613-5. 
t Proc. R. Irish Acad , ii. (1893) pp. 453-62 (5 figs.), 
I Zool. Anzeig., xvi. (1893) pp. 427-9. 
§ Ber. Verhandl. Sachs. Ges. Wiss. Leipzig, 1893, 325-30. 
|| Zool. Jahrb. (Abth. Anat.), vi. (1893) pp. 616-25 (5 figs.). 
^ Op. cit., v. p. 552. 
