98 MolL 
MOLLUSCOIDEA. 
The same so-called ‘ olfactory ’ tubercle has been the object of new 
researches by W. A. Herdman, who records a remarkable variability in 
it, not only as to genus and species, but even in the same species ; he 
also has “ grave doubts on the sensory function of this organ.” P. Phys. 
Soc. Edinb. 1881, 16 pp. ; abstract in J. P. Micr. Soc. (2) i. p. 726. 
A. DELLA Valle gives preliminary anatomical notes on the larvae and 
adult stages of several compound Ascidians ; he states that the axial cord 
in the tail of the larvae is a cylindrical canal full of a transparent and 
colourless liquid, that the amoeboid cells move about in the common 
mantle, that the endostyle is a gland, and that the circulation of the blood 
takes place exclusively by lacunae ; he has found a special oviduct in the 
Botryllidce^ analogous to that of the Salpce ; he also states the continuity 
of the ganglion with the vibratile groove. Particular attention is given 
to the relations of the peritoneal sac, which is, according to him, bilobed 
and interposed between the two primary sacs ; his observations on the 
development of the buds and of the embryo in the egg lead him to the 
conclusion that the Ascidians belong to the entrocoelous type. Atti Acc. 
Rom. (3) Trans, vi. pp. 14 & 15 ; abstract in Ann. N. H. (5) viii. p. 455. 
The segmentation of the egg of Lithonephria is described, with critical 
remarks, by A. Giard, C. R. xcii. pp. 1350-1352 ; abstract in J. R. Micr. 
Soc. (2) i. pp. 592 & 593 and Ann. N. H. (5) viii. pp. 64-66. The so- 
called cellulse of the green layer or of the granulosa do not belong origin- 
ally to the yelk, but originate from the follicle. 
W. A. Herdman notes several remarkable variations in the structure 
of the branchial sac observed in specimens of one species, viz., one fold 
only on the right and none on the left side, instead of four folds on 
either side, in Styela yrossularla (Beneden) ; the unequal or equal size of 
the transverse vessels in Ascidia (Alder) ; five to ten stigmata 
within the single meshes in Ciona intestinalis (L.); the presence or 
absence of delicate horizontal vessels, placed irregularly between the 
transverse vessels, and dividing the meshes into two parts, in Ascidia 
aspersa (Miill.). J. L. S. xv. pp. 329-332. 
Ascidij] SIMPLICES. 
Corella parallelogramma, Ascidia scabra and compressa^ Phallusia 
mentula, mammillata, and venosa^ are minutely described anatomically by 
C. Julin, Arch. Biol. ii. pp. 56-127, and Bull. Ac. Belg. (3) i. pp. 151-170 
& 895-900. 
The family of Gynthiidoc is re-defined with BoUenia, Guleolus, g. n., 
and probably Cystingia^ Mad., in a third sub-family Bolteni \i\ncti ; Herd- 
man, P. R. Soc. Edinb. xi. pp. 52 & 53. 
Microcosmus helleri, Australia, and propinquus^ Bass’s Straits, spp. nn., 
id. 1. c. pp. 54 & 55. 
Cynthia cerebriformis^ Port Jackson, fissa^ Bass’s Straits, /orwos«, and 
arenosa, Torres Straits, irregularis^ Port Jackson, hispida^ Bass’s Straits, 
and complanata, Port Jackson, spp. nn. ; id. 1. c. pp. 57-62. 
