On the Changes of Form in Fishes. 107 



Fig. 15. Parmula Batesii. Skeleton-spicule, to show the "abruptly- 

 pointed " form. 



Fig. 16. Tuhella reticulata. Skeleton-spicule, to sliow " rounded end." 



Fig. 17. XJruguaya corallinides. Skeleton-spicule, to show micropuncta- 

 tion and " rounded " ends. 



Fig. 18. Spongilla niteiis. Skeleton-spicule, to compare with foregoing 

 form. 



Characteristic skeleton-spicules of freshwater sponges from 

 Lake Baikal, after Dr.W. Dybowski ; traced off the figures in Taf. 

 iv. (No. 32), drawn with Hartnack's prism and no. 4 objective. 



Fig. 19. Luhomirskia haicalensis, Pallas : a, " parenchyma-spicule," after 

 Dybowski. 



Fig, 20. L. bacillifera, n. sp. 



Fig. 21. L. intermedia, n. sp. 



Fig. 22. L. pajn/racca, n. sp., two forms. 



X. — Spolia Atlantica : Contrihutions to the Knoioledge of 

 the Changes of Form in Fishes during their Growth and 

 Development, especially in the Pelagic Fishes of the At- 

 lantic. By Dr. C. F. Lutken. 



[Continued from p. 14.] 



8. Beama, Taeactes, Pteeycombus, Pteeaclis. 



With regard to Brama, it is to be remarked, in the first 

 place, that it has been ascertained that B. Raji is not an 

 almost exclusively Mediterranean species, but a bathyphilous 

 and very cosmopolitan species, which is spread from the 

 Faroes to the Cape, and represented at Chili, New Zealand, 

 and Japan by very nearly allied, if not identical forms {B. 

 japonica, Hilg., appears to be a distinct species), but has not 

 yet been found among the Antilles or on the eastern coast of 

 America. Leaving out of consideration some young forms 

 {B. Orcini, B. Dussumieri) which cannot pretend to the 

 rank of distinct species, a series of species from the Antilles, 

 Madeira, &c. have subsequently been described, some with 

 smooth scales, others, as in Pteraclis and Pterycombus, with a 

 large spine upon the anterior margin of the visible part of 

 each scale, and a corresponding notch in the posterior margin 

 of the immediately preceding scale. It is a singular thing 

 that it has not hitherto been observed that B. Raji, when 

 young but yet about half-grown (290 millims.), has the scales 

 armed with the same spines, which do not disappear until the 

 fish approaches its full development. We are therefore not 

 justified in forming a separate genus ( Taractes) for the species 

 of Brama with spines, nor in determining the young individuals 

 furnished with spines {Taractes asper, Brama Orcini and 



