370 MR. J. D. MACDONALD ON THE ANATOMICAL CHARACTERS . 
circular muscular fibres, while otters are scantily distributed in- Various directions over 
the body. 
The branchial network is very delinate and rests upon a stout transparent membrane, 
which is saceulated or embossed towards the respiratory cavity. | 
The internal tentacula are compound, as in the former species; and the mouth, stomach, 
_ intestine, testes, and ovaria exhibit the same general disposition, so that the description of 
those organs above given will equally apply to the present case, with the following excep- 
- tions, namely, that the stomach in the latter -is covered with a very dark pigmentary 
matter, probably including biliary follicles, and the intestinal loop is more > Opens so that 
the right testis and ovarium lie within it. 
- Finally, the heart holds a slightly oblique position below the left ovarium, and rests on 
a curved cylindroid body tinted with a rich madder-brown pigment, unquestionably the 
equivalent of the organ which I have assumed to be an “ elæoblast ” in the last-described 
species. | 
June 1858. 
EXPLANATION OF THE PLATE. 
Tas. LXIV. 
[The same general references apply to all.] 
L Cæsira ‘parasitica. King George's Sound species, 
Fig. 1. Animal in situ, with a cluster of zooids of Perophora Hutchisoni. 
a. Branchial, and 
5. Cloacal opening (both being contracted and radiately puckered). E 
Fig. 2. The animal removed from the test, to show its internal parts. 
€. Nervous ganglion. 
d. Position of the mouth. 
e. Stomach, and e. Liver, E Ep oc 
f. Intestinal canal and loop. i | | xs 
9. Rectum, | 
h. Right testis. - 
i. Right ovarium. 
Fig. 3. Simple external tentacula, magnified. 
Fig. 4. One of the compound internal tentacula. 
Fig. 5. Immature ova. 
Fig. 6. Perfect ovum with additional yelk-granules and outer covering. 
IL C. ficus. Shark Bay species (No. 1). 
Fig. 1. The animal as it appears in its natural State, with one or two Sertularians grow 
granular coat. ; 
ing on its 
