112 Dr. C. F. Liitken on the Changes of Form in Fishes 



shown that Stromateus securifer is only a young 8. argenteus 

 [candidus] ; and the subordination on the same ground of 

 Apolectus stromateus to 8. imru is confirmed by the descrip- 

 tion of a little fish (13 millims.) from the Straits of Riouw, 

 with large ventrals and the margin of the pra3operculum den- 

 ticulated, in which I have recognized a still younger form of 

 the Afolectus and of 8.paru. In consequence of these analo- 

 gies, and depending in part upon the materials at my disposal, 

 and in part on what I have found in the literature of the sub- 

 ject, it seems to me more than probable that 8. [Seserimus) 

 microchirus^ with more or less rudimentary ventrals, is a young 

 form of 8. jiatola ; but as this question, when once raised, may 

 easily be elucidated by the ichthyologists of the Mediterranean 

 coasts, I shall leave to them the task of solving it, and shall 

 not discuss it further. With regard to the genus 8tromateus 

 I shall further remark that the separation effected by M. 

 Bleeker of the three species 8. argenteus , cinerea^ and 

 sinensis {atous, albus) as forming a distinct genus, Stroma- 

 teoides, must be sustained. This genus is chiefly character- 

 ized by its short branchial clefts; young examples of 8troma- 

 teoides sinensis also confirm the proposition, already advanced 

 by M. Bleeker, that the ventrals, in this genus, disappear 

 earlier than in the true 8tromafeij if indeed they are not com- 

 pletely deficient. 8. medius, Pet., is a true 8tromateus, and 

 not a 8tromat€oides. 



The genus 8chedophilus , which belongs to the true pelagic 

 fishes, counts several (4) species ; I shall abstain from dis- 

 cussing whether it may not be necessary to make them 

 undergo some reduction. The pretty numerous specimens, 

 chiefly young, that our Museum possesses must all be re- 

 ferred to 8. medusophagus. The differences of age manifested 

 in the proportions of the parts of the body, the system of 

 coloration, &c. might certainly, if we examine them isolatedly, 

 give rise to the establishment of illegitimate species ; but they 

 have no great importance from a general point of view. 



The great differences arising from age, which, in the genus 

 Trachynotus^ have caused a series of false species, and even 

 genera [Doliodon, Bothrolo'.mns) to be established, have already 

 been dealt with by MM. Giinther and Gill, and I have nothing 

 essential to add. I shall only remark that T. rhomhoides of 

 the West Indies already has its rhomboidal physiognomy and 

 its much prolonged sickle-shaped fins at an age when these 

 prolongations of the fins are still rather short in the T. ovatus 

 of the Indian seas, and that I am of opinion (with Mr. Gill) 

 that these two species must be regarded, at least provision- 

 ally, as distinct. On the other hand, Micropteryx {Chloro- 



