EGGS AND LAKV^ OF TELEOSTEANS. 127 



by both parents. Spawning takes place in June and July on the west coast of 

 Scotland. The ovum has a single oil globule, and is hatched twenty-eight days 

 after fertilisation. The ovum of L. bimaculatus are always found adhering to 

 the inner surface of shells of Pecten operculatus; they are deposited likewise in 

 June and July, and are guarded by at least one of the parents. 



Div. XV. Acanth. Channiformes. 

 Fam. 1. Ophiocephalim:. 



These are fresh-water fishes of the Indian region. The male Ophiocephalus 

 is stated by Gunther to make a nest and guard the presumably adhesive ova. 



Div. XVI. Acanth. Labyrinthibranchii. 



Poly acanthus mridiauratus, Gunther, the Macropus viridi-auratus of 

 Lac^pede, commonly called the Paradise-fish, is a native of the East Indian 

 Archipelago, but is commonly kept in aquaria in Europe, and breeds freely in 

 confinement. Some account of the ova is given by Dr Miecz. von Kowalewski 

 in Zeit. f. wiss. Zool., Bd. xliii. The perivitelline space is small ; the yolk 

 apparently broken up into small masses, and large oil globules are present; but 

 the appearance of the living ovum is not described. 



Order II. ACANTH. PHARYNGOGNATHI. 



Fam. 1. POMACENTRIDiE. 



The ovum of Heliasis chromis is described by Hoffmann (loc. cit., p. 19). 

 The name he uses seems to be slightly erroneous. It is the Heliastes 

 chromis of Giinther's British Museum catalogue. The ovum forms a some- 

 what long ellipsoid with blunt ends, and at one of the poles is a group of 

 eight or nine long straight filaments attached at their basis to the vitelline 

 membrane. The micropyle is situated in the centre of the group of filaments. 

 Hoffmann remarks that the filaments in this ovum, and in Belone, Blennius, 

 Gobius, represent the external zona in adhesive ova such as Leuciscus and 

 Perca, in which the zona radiata is differentiated into two layers. On the other 

 hand, in pelagic ova, such as those of Scorpama, or in heavy non-adhesive ova, 

 such as those of Salmo, no division into two layers can be discovered in the 

 zona radiata. We may add to this comparison of Hoffmann's that it is pro- 

 bable from what Ryder observes concerning the development of the filaments 

 in Belone, that these processes are actually formed by a splitting up and 

 unequal development of the external zona ; and thus there is no fundamental 

 difference between the origin of the suspensory membrane in Osmerus eperlanus 

 and the filamentous processes in Belone, Atheinnichthys, Heliastes, &c. The 



