180 
MOLLUSCOIDA. 
[analogy], not by atavism, and that the true conformity of de- 
velopment goes no further than the formation of Rusconi^s cavity 
and the dorsal furrow within the egg. Arch. Z. exper. i. pp. 233- 
285. He also discusses the last paper by C. Kupffer (see above), 
and brings forward several objections to that author's conclusions. 
Ibid. pp. 397-428. 
H. Fol states that the cloaca in the Ascidia is due to a double 
invagination of the ectothelium, not merely to a hollow space 
between the strata of the skin, and that the endostyle is uni- 
form in all Tunicata. Mem. Soc. Phys. Genev. xxi. pt. 2 (sep. 
print, pp. 6 & 7). 
Lacaze-Duthiers recapitulates the researches of Kowalewsky, Kupffer, 
and others (Zool. Rec. vii. pp. 183 & 184, viii. p. 170) concerning the develop- 
ment of the Ascidians, in a very instructive paper, Arch. Z. exp^r. 1872. 
Another abstract of the same, illustrated by a plate containing figures 
copied from Kupffer’s paper of 1870, is given in J. Zool. i. pp. 187-192, 
pi. 12. 
Molgula macrosiphonicay sp. n., 0. Kupffer, Arch. mikr. Anat. viii. p. 369 
(pi. 17. figs. 1-8, egg and young state), Kiel. This species and M. affinis (A. 
II.) have no larval stage (see above), although in the longitudinal plaits 
of the branchial sac and the simple mass of the genital organ they resemble 
the other species of Molgulay and not any of the genus Eugyray in which, ac- 
cording to A. Hancock (see Zool. Rec. vii. pp. 184 & 186), tlje larval stage is 
wanting. Kupffer, ibid. pp. 368-369 ; abstracted, with critical remarks, by 
Giard, Arch. Z. exp^^r. i. pp. 397-404. 
M. adheermsy sp. n., Giard, 1. b. i. p. 405, Roscoff, Brittany. 
lithonepTirytty g. n., near Molgula, Tail of the larva as long as its body, 
which contains a reddish concretion. Molgxda complanata (A. H.) and X, 
clecipiexxsy sp. n., Roscoff : Giard, ibid. p. 406. 
Gymnocystisy g. n. Fixed, gregarious, with transparent shell ) larva with 
amoeboid appendages \ its tail thrice as long as its body. Q. comosay sp. n., 
Roscoff : id. ibid. pp. -^3 & 406. 
Cynthia mmtereymdSyS^. n., Dali, Am. J. Conch, vii. p. 167, Monterey. 
BoUenia bet'ingiy sp. n., id. ibid.y St. Paul’s Island, Behring Sea. 
CLAVELINIDiE. 
Clavelina lepadiformis (Miill.). Several varieties of it observed at Roscoff 
by A. Giard, 1. c. pp. 613 & 614. 
BoTRYLLIDiE. 
The aggregated and compound Ascidia of the north coast of France are 
arranged by A. Giard in the following manner : — 
Section 1. Oatenatjs. 
Tribe 1. Clavelinidse : Clavelina. 
Tribe 2. Perophoridae : Perophora. 
Tribe 3. Botryllidae : BotrylluSy Botrylloides. 
