REPOET ON THE TUNICATA. 
317 
Family VI. C(elocoemida:, n. fam. 
Colony massive, deeply concave on the upper surface, not attached. 
Ascidiozooids large, scattered all over the surface. Branchial apertures five-lobed. 
Test soft and gelatinous. Test cells numerous. Calcareous spicules present in 
the outer layer of the colony. 
r 
Branchial Sac large and well developed. 
Dorsal Lamina represented by a series of languets. 
Alimentary Canal extending beyond the branchial sac posteriorly, but not 
forming a distinct abdomen. Stomach smooth-walled. 
Reproductive Organs hermaphrodite in the adult Ascidiozooid. Testis com- 
posed of a number of pyriform vesicles, which join a spirally coiled vas 
deferens. 
The colony which will be described below under the name of Ccelocormus huxley 
is so remarkable in its structure, and differs so much from other Ascidiae Compositse, that 
I consider it necessary to form a new family for its reception. This family I would 
place, in a phylogenetic classification of the Tunicata, between Didemnum and Pyrosoma, 
so as to lie on the outskirts of the Ascidiae Compositae, leading in the direction of the 
Ascidiae Salpiformes. 
The colony in the only species known is massive, and is so deeply concave on the 
upper surface as to be cup-shaped or almost tubular (PI. XXXVII. fig. 2, and 
PI. XXXVIII. fig. 1). It is not attached, but was probably not free-swimming. There 
is only one common cloaca! aperture in the single colony, and it is placed at the bottom 
of the central cavity (see fig. 10, B, p. 320). From this cloacal aperture canals spread 
through the test, and connect the atrial apertures of the various Ascidiozooids. 
The branchial apertures are pentagonal or surrounded by five short lobes (PI. XXXVIII. 
figs. 2, 3). They occur not only on the outer surface of the colony but also on the inner 
wall of the central cavity (fig. 10, B, p. 320). 
In the shape of the colony, in its free condition, and in the form of the branchial 
apertures, this family difiers from all previously described Compound Ascidians, while 
in the condition of the test, the branchial sac, the dorsal lamina, and the vas deferens, 
it agrees with the Didemnidse. The presence of calcareous spicules in the test, and the 
spiral coiling of the vas deferens, especially indicate relationship to the Didemnidse, but 
it is interesting to find that although the vas deferens has the same arrangement as in 
the family Didemnidse the testis is quite different, and in place of forming one large 
ellipsoidal mass, it is divided into a number of distinct pyriform vesicles, as in the 
Distomidse or the Polyclinidse. 
The family contains the single genus Ccelocormus. 
