MisctUaneous. 257 



the specific characters of A. MuJdhans'iiii. The author minutely 

 describes the gradual changes that he observed. These were mani- 

 fested especially in the caudal part, and were accompanied by a 

 diminution of size. 



These observations, made upon animals living at freedom in salt 

 marshes, are coiToborated by experiments made by the author upon 

 Artemice reared in captivity in water of which the saltness was 

 gradually increased. Under these conditions he observed the same 

 transformations leading to the same forms. 



The inverse experiment was tried with Artemia MuMhausenii 

 taken in the salt marshes and reared in water rendered less and 

 less salt. This Artonia was then seen to retrograde by degrees 

 towards the form of Artemia salina. 



In proportion as the saltness increases or diminishes a correlative 

 increase or diminution of the surface of the branchiae is observed in 

 the Artemice. The form of these organs also differs in the two 

 species ; those of Artemia salina are of an elongated form, their 

 two dimensions being in the proportion of one to two, whilst those 

 of A. Miihlhausenii are oval, and their two dimensions arc in the 

 proportion of two to three. 



According to M. Schmankewitsch, the only(?) anatomical cha- 

 racter that distinguishes the genus Branchipus from Artemia is that 

 in the latter we count (including the two segments which bear the 

 external sexual organs) eight apodal terminal segments, the last of 

 which is nearly twice as long as the preceding one ; whilst in Bran- 

 cliipus there are nine apodal segments, the last two of which differ 

 but little from each other in length. When a series of generations 

 of Artemia have been reared in water less and less salt, the last 

 segment (^th) divides into two, when there are nine apodal seg- 

 ments as in Bratiehipns. Moreover it must be noted that in youth, 

 at the moment when they have just quitted the larval state, the 

 Branehipodes have only eight apodal abdominal segments, the last 

 of which has the same proportions as in Arteinia. 



It is not only by the number of abdominal segments that the 

 Artemice approach Brancliipus under the influence of the surround- 

 ing medium ; other characters which the former genus borrows 

 from the second also make their appearance ; this is the case, for 

 example, with the length of the caudal lobes, the number of setoe 

 the}' bear, &c. 



The results of these observations lead the author to the conclusion 

 that the Artemice which ordinarily pass their lives in strong salt 

 water are merely degraded forms of Brancldpodes, produced under 

 the influence of the surrounding medium. Inversely we may sup- 

 pose that the Branchipocli'S represent a form more advanced in deve- 

 lopment than the Artemice. 



The facts contained in M. Schmankewitsch's memoir appear to be 

 well observed, and possess great interest from the point of view of 

 the theory of transformism. We cannot, however, abstain here 

 from making one or two critical remarks : — first, that the author 

 makes no allusion to a rather important character which separates 



