88 General Notes. [January, 
of mammals. In Hyrax I find a small bone between the astragalus 
and navicular, which I can only homologize with the “ sesamoid.” 
In the carnivores it appears to be coalesced with the navicular, as 
in Lepus, for I always find in the ascending part of the navicular 
traces of a former separation. In an embryo of a dog of 65™™ I 
have observed indications of a former distinction. In a recent 
examination of Ornithorhyncus! I have observed the same con- 
dition as in Cercolabes; the spur of the former is homologous 
with the claw-like piece in this rodent. A similar condition is 
found in many Edentates. 
The question now is, what is the homologue of this bone? I can 
only compare it with the tibiale. The astragalus would then be 
homologous with the intermedium, the calcaneum with the 
fibulare. 
I reach the conclusion: First, by the position of the piece in 
question; it lies in the first row of tarsal bones next to the astrag- 
alus; second, by the development of the tarsus of mammals. 
never have been able to distinguish an “intermedium ” in the 
sense of Bardeleben. In embryos of mammals, I have always 
found the astragalus composed of one piece, and I never find an 
element between the astragalus and calcaneum. In adult mam- 
mals, especially in Marsupials, I find Bardeleben’s “ intermedium ” 
well developed, but I only consider it a tendon ossification. 
The terminology of the tarsus of mammals would be the fol- 
lowing: 
Tibiale =s Sesamoid, 
Intermedium bs Astragalus 
Fibulare — Calcaneum. 
Centrale sets Naviculare (Navic. = Centr. + Tib.). 
Tarsale 1 == Cuneiform 1. 
Tarsale 11 = Cuneiform 11. 
Tarsale III = Cuneiform 111. 
Tarsale Iv + v Cuboideum, 
If we seek for connecting forms among the vertebrates below 
the mammals, we must bear in mind the Theromorpha from the 
Permian recently described by Cope, which show so many resem- 
blances to the mammals, especially in the tarsal bones. T do mot 
hesitate to consider the claw-like piece in the tarsus of Cerco- 
labes and Erethizon and the spur in the monotremes as the rudi- 
ment of a sixth toe, and would like to compare it with the same 
structure seen in the tarsus of frogs. 
In my paper on the morphogeny of the carpus and tarsus of 
the vertebrates I will speak further on this subject—Dr, G. Baur, 
Yale College Mus., New Haven, Conn., Oct., 1884. 
OOLOGICAL Notes.—Celenterates—Messrs, Koren and Dan- 
iellsen have recently described fifteen new species of Alcyona- 
*Copėë, E. D., Paleont. Bull. No. 39, p. 46, 1884. 
AAEN SN 
noe RD EE 
