TUNICATA, 
Moll. 97 
Naples. New compound Ascidians, A. della Valle. Atti Acc. 
Rom. (3) Trans, vi. p. 14 ; abstract in Ann. N. H. (5) viii. p. 455. 
The Cynthiidm and Molgulidm collected during the ‘ Challenger * 
expedition, are described by Herdman, P. R. Soc. Edinb. xi. pp. 52-88, 
& 233-240. Several new abyssal species have an exceedingly wide 
distribution. Caleolus^ Styela, and Abyssascidiaave the only genera found 
in depths exceeding 500 fath. 
R. O. Cunningham’s paper on the Tunicata of Magellan Straits, in 
Tr. L. S. xxvii. [1871], has been omitted from the former Records; it 
contains descriptions of several then new species of Ascidians and 1 new 
genus, the latter will be mentioned hereafter. 
Ascidijc. 
E. VAN Beneden, having examined the development of the mesoderm, 
heart, and sexual organs in Phallusia, Ciona^ Perophora, and Clavellina^ 
comes to the conclusion that a coelom, or true abdominal cavity, exists 
only in the larval stage in the Ascidians ; the epithelial cells, which line 
it, expand afterwards, and closing together form a continuous mass or 
secondary mesenchym, which is, by its origin, distinct from the primitive 
mesenchym of the Codenterata and Vertehrata. The pericardial cavity 
of the Ascidians is, according to him, homologous to that of the Verte- 
brata. Zool. Anz. iv. pp. 375-378, & C. R. xciii. pp. 1238-1241 ; 
abstract in J. R. Micr. Soc. (2) i. p. 727, & ii. p. 180. 
C. Julin describes the organization of the simple Ascidians, and par- 
ticularly some of their finer histological structure ; he terms the side of 
the endostyle ‘ ventral,’ and the space between the oral and cloacal orifice 
‘ dorsal,’ regarding the oral orifice as the homologue of the mouth of the 
Vertebrata ; and he finds that the body wall of an Ascidian is formed of 
the same parts as that of Amphioxus. The epibranchial and peritoneal 
grooves are invested by a vibratile epithelium, and they probably drive 
the nutrient matters towards the oesophagus. The ganglion consists of 
an external layer of grey matter, solely formed of unipolar ganglionic 
cells, and of an inner white substance, formed of nerve fibrils and smaller 
nerve-cells. In all Ascidians there is a glandular organ, which, in situa- 
tion, relations, texture, and probable origin, may be regarded as the homo- 
logue of the hypophysis cerebri of the Vertebrata. It is situated imme- 
diately below the brain, and contains an excretory canal, which opens by 
a ciliated infundibulum into the buccal region ; its orifice is situated on a 
special tubercle, which has not, as supposed, any olfactory function. In 
Phallusia mammillata the efferent duct of this organ has several branches, 
which open into the peribranchial cavity. — Further studies lead the 
author to suggest that this ‘ hypophysis ’ may be an excretory organ, and 
functionally comparable to a kidney. Unlike most glands, there is more 
than one excretory orifice ; 128 ciliated infundibula were found completely 
developed in one not adult individual. Arch. Biol. ii. pp. 59-127 & 
211-232, with 5 plates. Abstracts in J. R. Micr. Soc. (2) i. pp. 590-592 
& 726; also in Bull. Ac. Belg. (3) i. pp. 151-170 & 895-900, in Arch. Z. 
exp4r. ix. p. 30, and in Kosmos, ix. p. 387. 
