VERTEBRATE ZOOLOGY. 495 



3. There exists no trace of a deciduous membrane. 



4. The allantois with its vessels extends over the entire in- 

 ternal surface of the chorion, to which it is intimately con- 

 nected. 



5. The umbilical cord has a very short trunk, from which 

 diverge four much longer branches, each composed of an ar- 

 tery and a vein, which extend and ramify on the inner sur- 

 face of the placenta. 



6. The amnion invests the trunk as well as branches of 

 the umbilical cord, and binds the latter by membranous la- 

 mellae. Its surface is entirely smooth. 



V. The internal surface of the placenta carries a large num- 

 ber of appendages which are diverticula of vessels as well as 

 veins. In the interior of these diverticula is found an areo- 

 lar tissue. 



8. The umbilical vesicle has disappeared, or, at least, there 

 exists only a rudiment in the trunk of the umbilical cord. 



In brief, the Sirenians present a diffuse placenta icithout a 

 decidua, and in this respect resemble the Cetaceans as well 

 as Ungulates, but, on a more detailed comparison, in the opin- 

 ion of Dr. Harting, they agree more nearly with the Ungu- 

 lates than with the Cetaceans. For the full exposition of 

 the resemblances and differences, as well as reasoning on the 

 facts, we must refer to Dr. Harting's memoir. 



A Supposed New Gorilla. 



It may be of interest to many of our readers to learn that 

 a skeleton and skin of an adult female gorilla have lately 

 been sent from Landana, Congo, which exhibit considerable 

 differences from specimens previously obtained, and which 

 have, therefore, been discriminated under the new specific 

 name Gorilla mayema, by MM. Allix and Bouvier, of Paris. 

 The supposed new species is said to be of considerably small- 

 er size than the common species. In the skull, differences are 

 observable in the depth of the temporal fossa?, the narrow- 

 ness of the cranium behind the orbital arches, the narrowness 

 of the interorbital space, and a greater prominence of the 

 keel which rises in the middle of this space, the length and 

 flattening of the zygomatic arches, and also a very noticeable 

 diminution of the height of the spinous apophyses of the first 

 cervical vertebrae. Furthermore, " the back is thickly cov- 



