267 
The muscular system of the trilobites must have been 
highly organized as in Limulus, as like the latter they pro- 
bably lived by burrowing in the mud and sand, using the 
shovel-like expanse of the cephalic shield in digging in the 
shallow palzozoic waters after worms and stationary soft- 
bodied invertebrates, so that we may be warranted in sup- 
posing that the alimentary canal was constructed on the 
type of that of Limulus, with its large, powerful gizzard and 
immense liver. 
Notes on Aprenpicunaria and the Larvat Conpiti0n of an 
ACANTHOCEPHALOID Sco.ecip from the Coast of Portvu- 
Gat. By W. Savitte Kent, F.Z.S., F.R.M.S., &c., of 
the Geological Department, British Museum. 
Tue figures accompanying this communication illustrate 
two floating forms encountered last summer during my 
dredging trip with Mr. Marshall Hall and Mr. Edw. Fielding 
to the coast of Spain and Portugal, in the former gentle- 
man’s commodious yacht the “ Norna.” 
The two ‘were observed on one occasion only, early one 
calm morning in June, when the surface of the sea was like 
amillpond. Both occurred in large patches, at the surface 
of the water, and as they floated past the vessel received 
from our crew the very comprehensive term of “ spawn.” 
The microscope, however, or the unassisted eye even at 
close quarters, speedily revealed to us that they were bodies 
of a far higher type, in the literal sense of the term, than 
had been accredited to them, and at the same time, that the 
two were essentially distinct from one another, in both histo- 
logical structure and general form. 
A perfect individual of the first of these (Pl. XIV, figs. 1 
and 2) might be described as a minute hyaline body, roughly 
resembling, in configuration, a transparent tadpole, having 
an inflated anterior portion divided into two separate cham- 
bers, with a dependent tail-like appendage attached to it, 
whose rapid vibrations served to propel the organism through 
the water. The two chambers of the body proper differed 
considerably in size, as also in the nature of their respective 
contents and colorisation, the anterior and larger one being 
completely filled with pale amber-coloured spherical bodies, 
varying in number from 80 to upwards of 100, which must 
undoubtedly be identified as ova, while the posterior, and by 
