642 SCIENTIFIC RECORD FOR 1884. 



vailed, and in time not even the remembrance of the facts was left. 

 During- the past year, however, the reliability of the old naturalists has 

 been verified by two independent observers, Mr. W. H. Caldwell and 

 Dr. Wilhelm Haacke. Mr. W. H. Caldwell, who, it may be remarked, 

 was the first Balfour student, went to Australia, partly at the expense of 

 the British Association for the Advancement of Science, for the purpose 

 of studying the embryology of the Monotremes and Ceratodus. In Sep- 

 tember a telegram was sent to the British Association informing its mem- 

 bers that "Caldwell finds Monotremes oviparous; ovum meroblastic." 

 About the same time Dr. Haacke found an egg in the Australian 

 Echidna or Tachyglossus. The two animals, however, differ consider- 

 ably in their disposition of the egg. The aquatic OrnithorhyncJms ex- 

 cavates a deep hole in the banks, which it enters by an opening under 

 the water, and in its burrow it forms a kind of a nest in which it de- 

 posits two eggs. The terrestrial Tachyglossus produces only one large 

 egg having an essential resemblance to that of the Ornithorhynchus, but 

 transfers it to its mammary pouch, wherein it is hatched. 



The statement that the egg is meroblastic, which the telegraph con- 

 veyed to the British Association, demands a word of explanation. This 

 means that only a portion of tlie egg is involved in the original segmen- 

 tation, and that the rest is a food-supply for the early developing em- 

 bryo. In other words, the egg resembles that of a bird or reptile, and 

 differs from the minute one of the other mammals. 



For other facts in the long and interesting history of the Monotremes 

 the various articles elicited by the new discovery may be referred to. 

 {Zool. Anzeiger, December 1; iScience, V, p. 3; Science, iv, p. — ; Nature, 

 XXXI, pp. 132-135 ; Bevue Scientijique, xxxv, pp. 657-659.) 



The species of Tachy gloss fds. — In the early part of the past century a 

 strange spine-bearing mammal of Australia was made known under 

 the name of Echidna aculeata, and is now generally known as the Tachy- 

 glossus aculeatus, the former name having been previously given to a 

 genus of fishes. For a long time it was the only known species of the 

 type, and the genus was supposed to be peculiar to Australia ; but 

 within the past decade no less than three species have been obtained 

 from New Guinea, and two of these are so different from the long- 

 known Australian species (and another related one discovered in New 

 Guinea) that they have been generically separated. We have, there- 

 fore, now four species, or, if we give specific rank (as some may con- 

 sider to be most natural) to the form occurring in Tasmania, we have 

 five species of this interesting family. These are as follows : 



1. Tachyglossus aculeatus, of Southern Australia. 



2. Tachyglossus setosus, of Tasmania or Van Dieman's Laud. 



3. Tachyglossus Laicesii, of Southern New Guinea. 



4. Zaglossus Bruynii, of Northern New Guinea. 



5. Zaglossus mllosissimus, also of New Guinea. 



