502 PROCEEDINGS OF SCIENTIFIC SOCIETIES. 
oracic segments being added during after life. The circular larva of 
~ hirsuta, which has no thorax, or at least a very rudimentary Mo 
gion, and no pygidium, approaches nearer to the —€— form of t 
Piyllopods, though we would contend that it is not a Naupliu 
larva passes through a slightly marked Pan e oe It differs 
om the adult simply in possessing a less number of abdominal feet 
(ilis), and in having only a very rudimentary s pine. Previous to hat tch- 
ing it strikingly resembles Trinucleus and ERES trilobites, suggesting 
that the two groups should, on embryonic and structural grounds, be 
included in the same order, especially now that Mr. E. Billings* has de- 
monstrated that Asaphus possessed eight pairs of five-jointed legs of 
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sexually, and the eggs were probably laid in the sand or mud, and im- 
pregnated by the sperm cells of the male, floating free in the water. 
The muscular system of the trilobites, must have been highly organized 
as in Limulus, as like the latter they probably lived by burrowing in the 
mud and sand, using the shovel-like expanse of the cephalic shield in 
digging in the shallow palæozoic waters after worms and stationary soft 
bodied invertebrates, so that we may be warranted in supposing that the 
imentary canal was constructed on the type of that of Limulus, with its 
large, uae gizzard and immense liver. 
ILL presented a verbal communication ** On the Relations of the 
Orders of Mammals.” He stated that in order to render at once appreci- 
ate the guiding principles by which he had been influenced. 'These were 
ve: 
1st. Morphology is the only alb guide to the natural classification of 
organized beings; teleology or physiological adaptation the most unsafe 
an 
ications of any single organ. 
Rus ee er ye 
* Proceedings of the — Society of London. € = T » June 2, 1870. 
In this communication Billings announees the impo very of a — of 
Asaphus platycephalus, probe that the e anim mal possessed PPA pes of five-jointed 
