254 SUMMARY OF CURRENT RESEARCHES RELATING TO 



of the uterus, and with a discharge from the generative orifice. Com- 

 plications may include rupture of the congested vessels of the hyper- 

 trophied superficial uterine mucosa, and extravasation of the blood 

 contained therein, or a discharge of this blood into the uterine cavity 

 .and thence to the exterior, or more or less denudation of the mucosa 

 leading to the formation of a menstrual clot. 



The rupture of the vessels of the mucosa and the subsequent phe- 

 nomena are supplementary to the essential factors of pro-oestrum ; they 

 occur in part rarely in some animals, in part always in some animals, 

 but in a complete sequence only, so far as is known, in the Primates. 



Mr. Heape discusses at some length the relations between " heat " 

 and menstruation. There is a congestion of the generative organs in 

 both ; there may be a recurrence of " heat " as there is a recurrence of 

 menstruation ; the discharge during " heat " may be of a menstrual 

 character, and from a phylogenetic point of view the homology of the 

 two processes is to be expected. Seven objections by those who deny 

 the homology are considered, and the author concludes that the evidence 

 of the homology, not only of pro-oestrum and menstruation, but of 

 each of the various sexual phenomena in the different mammalian types, 

 is incontrovertible. 



Speaking generally, the rhythm of the sexual season and the power 

 of breeding are seasonal ; they are governed by external forces which are 

 exerted in consequence of seasonal change, and by internal forces which 

 are dependent upon individual powers. Further, there is abundant 

 evidence that nutriment and the capacity for storing nutriment, and the 

 energy resulting therefrom, are essential factors. The author does not 

 agree with Beard that the ovary is the seat of the governing power of 

 the breeding function ; thus ovulation and the oestrus cycle are not 

 necessarily coincident, nor are their initiatives mutually dependent. 



Heape suggests the probability that there is in the blood from time 

 to time an oestrus toxin, that its presence is due to the external and 

 internal forces mentioned above, and that to it may be referred the 

 power which stimulates the activity of the sexual season and brings 

 about the actual production of those generative elements which nutri- 

 tion has enabled the animal to elaborate. Perhaps research in this 

 direction would lead to increase of knowledge regarding some of the 

 causes of sterility. 



Eggs of Myxine.* — A. S. Jenson obtained from the Faroes somo 

 eggs of Myxine ghitinosa, which were attached to the free ends of a felt- 

 work woven around a dead branch of Cellepora. The clusters were ob- 

 tained in the beginning of June, 8 (Danish) miles from land, at a depth 

 of 125 fathoms, on a bottom apparently of sand. It is inferred that the 

 hag lays its eggs on solid bodies which are enveloped in slime, that the 

 eggs are fastened to this slime by means of the anchor-shaped stalks 

 from the opercular pole, and that the anchors of the opposite pole are 

 also enveloped in slime, and serve for the attachment of a second egg, 

 and so on, so that short chains of three or four eggs result. The oper- 

 cular pole is perforated by a fine micropylar canal, but the eggs were 

 unfertilised. It is supposed that the eggs are not laid on the muddy 



* Vidensk. Meddel. Nat. For. Kj'obeuhavu, 1900, pp. 1-14 (1 pi.). See Zool. 

 Centralbl., viii. (1001) pp. 125-0. 



