4GG 
MR. W. II. CALDWELL ON THE EMBRYOLOGY 
1300 and 1400 Echidna of both sexes, from which a fairly complete series of stages 
was obtained. A skilful black, when he was hungry, generally brought in one female 
Echidna, together w T ith several males, every day. The former seemed to be much 
more difficult to find than the latter at this season. The blacks were paid kalf-a- 
crown for every female, but the price of flour, tea, and sugar, which I sold to them, 
rose with the supply of Echidna. The half-crowns were, therefore, always just 
sufficient to buy food enough to keep the lazy blacks hungry. The supplies were 
carried on a six-horse dray, and the light buggy with four-in-hand proved very much 
more convenient than the heavier trap of the year before. In September my friend 
Bloxsome superintended the transfer of the camp to the colder river Mole, further 
south, where we hoped to dig out the later stages of Ornithorhynchus from their nests. 
1 employed some white navvies, who opened up a large number of burrows ; but the 
renewed exposure in Queensland had brought on my fever again, and this seriously 
interfered with the completion of the Ornithorhynchus series. 
The later stages of Monotreme development have, therefore, to be worked out, mainly 
with Echidna material. 
Previous Investigations. 
Before entering on the embryology of the Monotremes, it wfill be, perhaps, interesting 
to trace the history of opinions held concerning them during the long period of ninety- 
two years which elapsed from their discovery in 1792 until the complete series of the 
stages in development were found in 1884. Nearly all the different views held 
concerning the nature of the female product in Monotremata have been based on 
indirect evidence, derived from the anatomy of the adult. 
Shaw (53 and 54), # who described Echidna in 1792, and Ornithorhynchus in 1799 
[Platypus), classed them with Edentata. 
Blumenbach (13), after studying the skull in 1801, suggested that they might 
prove to be oviparous (14). Sir Everard Home (35), in the same year, relying 
chiefly on the absence of mammary glands and the presence of a cloaca, compared 
/ 
them with the ovi-viviparous Sharks and Reptiles. In 1803 M. Etienne Geoffroy 
Saint-Hilaire (19) proposed the name “ Monotremata,” without definitely assigning 
them a place in the zoological series. Between 1802 and 1819 no new facts were 
discovered, and in the text-books the animals were classified, either as Mammals, 
between Edentata and Rodentia (Desmarest, 1804), or as forming an appendix quite 
at the end of the Mammalian series (Tiedemann, 1808 ; Illiger, 1811), or as outside the 
Mammalia, and “ very probably” oviparous (Lamarck, 1809). In 1812 de Blainville 
(9) pointed out the resemblance to Reptilia, presented by the urino-genital apparatus 
and the shoulder-girdle ; but he considered the resemblances to Mammalia, and espe¬ 
cially to Marsupialia, much more marked. In 1817 Cuvier and Oken still kept the 
* The numbers in parentheses refer to the alphabetical List of Works at pages 480-484. 
