Royal Academy of Sciences of Paris. 161 



2. Synotus. Cephalic elements double as to the medulla ob- 

 longata and cerebellum ; the rest of the head single. Ears super- 

 numerary, and united behind the head. 



3. Eniops. Cephalic elements double as to the medulla ob- 

 longata, cerebellum, and optic lobes; rest of the head single. 

 Supernumerary ears behind the head, and an additional eye in the 

 sinciput. 



4. Janiceps. The whole encephalus and organs of senses double ; 

 the faces opposite each other. 



Examples exist of each of these classes, but the first has only 

 recently been met with. The name given by M. St. Hilaire to the 

 family is that of " Monstres bicorps unicephales." 



MISCELLANEOUS. 



Chronology of the Egyptians. A considerable portion of the 

 sittings of the 4th and llth of April was taken up by the communi- 

 cation of a memoir by MM. Biot and Champollion on this interest- 

 inn; subject. It is well known that the Egyptians divided the 

 year into twelve months of thirty days each which, with five 

 intercalary or supplementary days, completed the number of 365. 

 Twelve great divinities presided over the twelve months of the year, 

 five others over the five intercalary days ; thirty genii regulated the 

 thirty days of the month ; and the twenty-four hours of the astro- 

 nomic day were under the protection of twelve gods and the same 

 number of goddesses. This year of 365 days was, however, about 

 a quarter of a day shorter than the solar year, whence the first day 

 of the month of Thot, which began the year, was perpetually in 

 advance of the sun's progress in the ecliptic: so that if the 1st of 

 the month of Thot occurred at the vernal equinox, it would, in four 

 years* be one day before it; and so on in progression until the ex- 

 piration of 1506 years, when it would again occur at the precise 

 period of the equinox. Hence the Egyptian year was termed annus 

 vagus ; and so great was the attachment of the country to it, that 

 the kings, on coming to the throne, were compelled to take an oath 

 against allowing any change to be made in the mode of computing 

 the year ; and the compulsory correction made in the calendar by 

 Augustus, twenty-four years before Christ, was considered one of 

 the bitterest fruits of the Roman conquest. This attachment was 

 not founded on ignorance ; on the contrary, the Egyptians were 

 well aware that the solar year was about a quarter of a day longer 

 than their annus vagus, and were probably even the first to commu- 

 nicate that fact to the Greeks. This strong attachment to the annus 

 vagus is the more remarkable, when we consider that none of their 

 monuments give us any reason to suppose that these years were 

 connected by them in any regular chronological series ; on the con- 

 trary, all the Egyptian dates which have reached us are reckoned 



VOL. II. AUG. 1831. M 



