IGO 
SUMMARY OF CURRENT RESEARCHES RELATING TO 
Of the Crustacea, the Isopoda and Amphipoda are alone reported on in 
this number. 
Relationship of Annelids and Molluscs.* — M. A. Giard draws 
attention to a report of the Academy of Sciences in which M. Roule is 
credited with poiuting out the relationship of Annelids to Molluscs ; 
and lie gives quotations from papers of his own, one as early as 1876, in 
which that affinity was urged. He found some difficulty in homologizing 
the schizocoele of the higher Gymnotoka(= Mollusca, Annelida, Brachio- 
poda, and Oiliata), with the enterocoele of such lower members as the 
Brachiopoda and Sagitta. Now, however, he feels he may generalize ; 
he finds that when, in the develojmient of allied animals, an organ some- 
times arises by a ju’ocess of invagination or folding and at other times 
by cleavage or hollowing out, the latter mode of formation is to bo 
considered as a condensation of the former. M. Giard has not seen in 
any of the embryonic Annelids which he has studied, the syncytium 
described by Roule ; indeed, the contours of the ectodermic cells may 
always be demonstrated by suitable reagents. 
Mollusca. 
Sensory Organs of Lateral Line and Nervous System of Mollusca.t 
— Dr. J. Thiele was led to investigate the sensory organs of the lateral 
line in Molluscs from a suspicion that the abdominal sensory organs of 
Lamellibranchs might be the homologues of those found in the Capitel- 
lida). In a small Mediterranean Chiton, which perha23S deserves to be 
jdaced, on account of its ^peculiarities, in a special genus, eye like organs 
were seen which presented considerable differences from those described 
by Moseley, and in addition, there were movable setae at the sides of 
the body which appeared to be tactile organs. In the nervous system 
tlie swellings of the dorsal ring which are regarded as cerebral ganglia, 
the direct connection of the latter with the anterior visceral ganglia, 
and, above all, the numerous connectives between the ventral and lateral 
cords are of importance. The- author has observed in a Proneomenia 
hypodermal ^processes, which are similar to those described by Hubrecht 
in P. Sluiteri, but they differ in having no spicules, and are regarded as 
sensory organs. Young specimens of Area Nose have in the anterior 
part of the mantle two proportionately large pigment cups, the concavity 
of which is directed to the sides. Lateral organs such as those known 
in Fissiirella and Trochus have been discovered in Haliotis, and are 
described by the author ; these are not limited to the epipodium, but 
are found also on other parts of the body. The cephalic tentacles are 
regarded as the anterior terminal tentacles of the epipodium. 
The nervous system of Haliotis is described as having the upper 
oesophageal ring divided into three portions which lie one above the 
other; of these the lowermost becomes separated to form a commissure 
beneath the cesoxphagus, while the two others pass into the plcuropedal 
connectives. 
Proofs are afforded by comparative anatomy that the upper oeso- 
phageal ganglia of Poly clads. Annelids, and Solenogastres are not 
♦ Comptes Rendns, cx. (1890) pp. 90-3. 
t Zeitsclir. f. Wiss. Zook, xlix. (1889) [1890], pp. 385-432 (2 pis.). 
