Miscellaneous. 415 
animal seizes the penis of the male between its cirri and drags it 
inside its valves, where it retains it, unless the latter, as is often the 
case, penetrates thither by itself. The animals remain in this way, 
pressed one against the other, producing little movements of con- 
traction. Emission takes place, and the sperm is always deposited, 
in the form of a gelatinous mass, beneath the ovigerous frenum on 
each side of the body. On each occasion that I noticed it it was 
the smaller animal of the two that played the part of the male. 
If there are several specimens of Lepas or Balanus whose sperma- 
tozoa are ripe surrounding another individual which is ready to be 
fertilized, it is not unusual to see several of them participating in 
the fertilization of the same individual. 
Another phenomenon is frequently witnessed which is strange 
enough to be worthy of mention. Two Balani (B. tintinnabulum) 
are attached to the same fragment of rock, both of small size, and 
both with the cirri extended in the same direction. The hinder- 
most one wishes to fertilize its neighbour: it tries, but its penis is 
too short and cannot reach as far as the orifice of the chamber in . 
order to deposit its sperm there. Then, by a simple process which 
might be termed ingenious, it turns abruptly in its chamber about 
three quarters round, and thus diminishing the space which sepa-, 
rates them by the length of the orifice of the chamber, it is able to 
succeed in fertilizing its neighbour. 
From these facts, and others which cannot find a place in this 
note, we must conclude that the ordinary mode of fertilization in 
the Cirrhipedes is reciprocal. When this method is rendered 
impossible, by various circumstances, more especially by the fixation 
of the animals, self-fertilization may also take place. 
There is no actual copulation, but merely approximation of the 
sexes and deposition of fertilizing matter in the neighbourhood of 
the oviferous females. 
It was impossible to determine the existence of reciprocal fertili- 
zation in Pollicipes ; I am inclined to believe that in this case there 
is only simple self-fertilization.—Comptes Itendus, t. cxili. no. 20 
(Noy. 16, 1891), pp. 706-708. 
On the Embryogeny of Sagitta. By M.S. Jourparn. 
Observations made on the development of Sagitta have led me to 
differ from Kowalewsky and Bitschli in my conception of the 
formation of the archenteric cavity, which appears in these animals 
at the gastrula stage. According to the naturalists mentioned, this 
cavity, which is simple at first, should divide at its anterior region 
into three lobes, while preserving its simplicity in its posterior 
portion. ‘The lateral lobes of the tripartite region would constitute 
the general body-cavity ; the median lobe would form the digestive 
canal of the perfect animal. This view appears to me to be 
erroneous. 
The archenteric cavity, open behind at the blastopore, which 
occupies the region of the future anus, gives rise not to the general 
