128 MR J. T. CUNNINGHAM ON THE 



yolk of Heliastes resembles in structure that of the herring, being composed of 

 a number of ellipsoidal vitelline discs; but there is also present a large oil globule 

 at the vitelline pole. The protoplasm in the mature unfertilised ovum forms as 

 usual an envelope round the vitellus which is thickest beneath the micropyle, 

 and thins away all round that point. The blastodisc and blastoderm during 

 simple segmentation is large in proportion to the yolk. The perivitelline space 

 is considerable. Hoffmann gives no figures of the embryonic or larval stages. 



Fam. 2. Labrid^e. 



The development of a large number of the wrasses has been studied. 



Tautoga onitis, Linn. — The pelagic ova of this species are described and 

 figured in Pelagic Stages. The diameter of the ovum measures '90 to "95 mm. 

 The yolk is homogeneous, and there is no oil globule ; the perivitelline space 

 is of moderate dimensions. The newly hatched larva is 3 05 mm. in length; 

 the rectum is not in contact with the yolk sac, but at a distance of *55 mm. 

 from it (not nearly so far back as in Clupea). The anus is open, the notochord 

 multicolumnar ; the eye is scarcely pigmented, but there are small compact 

 pigment spots along the dorsal region of the sides of both body and tail ; the 

 pectorals are scarcely developed, the ventrals not at all. The eggs of Tautoga 

 were artificially fertilised, so that the identity of the ova and newly hatched 

 larvie is certain. But the authors point out that the ova of Ctenolabrus, 

 Ps. melanogaster, and Tautoga are so similar, both in structure and size, that it 

 is scarcely possible to distinguish them with certainty in the produce of the 

 tow-net. The authors state that figs. 1, 2, 3, and probably fig. 4 (in my 

 opinion fig. 4 also, certainly) in plate vi. of Young Stages, part ii., belong to 

 Tautoga, and not to Pseudorltombus melanogaster. Thus the position of the 

 rectum with respect to the yolk sac in the newly hatched larvae is shown 

 to be a constant family character ; and there is no exception to the statement 

 that in Pleuronectidge the rectum at that stage is in contact with the yolk sac. 



Ctenolabrus adspersus, Walb. (C. coeruleus, Storer). — The ova of this 

 species have been described by Agassiz and Whitman in Pelagic Stages, and 

 by Kingsley and Conn. The ovum is "85 to "92 mm. in diameter. Before 

 fertilisation the peripheral layer of protoplasm is densely filled with refractive 

 granules, which render the ovum opaque; but after fertilisation the granules 

 disappear, and the egg becomes perfectly transparent. In the newly-hatched 

 larva the rectum is separated by *25 mm. from the yolk sac, the total length of 

 the larva being 2*30 mm. There are black dendritic chromatophores along the 

 sides of the body and tail. The time required for hatching varies from two to 

 six days. The eggs are shed at Newport in the months of May and June. 



The ova of Julis vulgaris are described by Hoffmann (loc. cit., p. 43). The 

 diameter of the ovum measures 75 mm. The yolk is homogeneous, but con- 



