November 16, 1883.] SCIENCE, 



The specific distinctness of the American and 

 European brine shrimps. 



In Professor Smith's notice of our 'Monograph of 

 phyllopod Crustacea,' he states, that, in the portion 

 relating to the above subject, ' there is certainly con- 

 fusion,' and quotes two paragraphs relating to the 

 females alone, and finally remarks, "but differences 

 like these in statements of observation betray inex- 

 plicable carelessness." 



After quoting the two paragraphs relating to the 

 females alone, it seems to us a careful critic would 

 have also taken pains to have quoted the longer para- 

 graph relating to the males, which directly follows 

 the first paragraph quoted by our critic. To allow 

 the two paragraphs relating to the females to be so 

 widely separated was an oversight on the part of the 

 author, who, however, thought that he had taken a 

 good deal of pains to show the specific distinctness 

 of the American and European species. Two sets of 

 females from different localities, named by different 

 persons, were examined at different times ; and this ex- 

 plains how the two paragraphs became placed too far 

 apart in the author's copy. It would have been bet- 

 ter, of course, if the author had added a few words, 

 and dogmatically stated that the two species were 

 undoub'tedly distinct. He preferred not to do, or 

 omitted to do, this, but gave in considerable detail, 

 and in as judicial a way as possible, the facts of the 

 case. At first it was ' difficult to find good differential 

 characters' between the females, and those found are 

 but slight ones. The females of any of the species of 

 Artemia, Branchinecta, or Branchipus, do not exhibit 

 good specific characters; but the males do, as the 

 author attempted to show. If the author failed in 

 directness of statement on this subject, or led to any 

 confusion in any one's mind, he sincerely regrets it: 

 on the other hand, he doubts whether there were, 

 in the case, reasons for the charge of 'inexplicable 

 carelessness.' 



The paragraph which Professor Smith would have 

 done well to have quoted is the following one : — 



" Upon compariBg a good many males from Great Salt Lake 

 with several, both stained with carmine and unstained, received 

 from Cagliari, Sardinia, through Prof. J. McLeod of Ghent, the 

 European A. salina is seen to be considerably stouter, the head 

 wider, the eye-stalks lonser and larger, and the eyes larger. 

 The frontal button-like processes of the first joint of the claspers 

 are nearly twice as large as in the American species, and a little 

 more pointed, while the claspers themselves are larger and 

 stouter. The legs and sixth endites are of about the same form. 

 The most apparent difference is in the caudal appendages, or cer- 

 copods, which in A. salina are several times larger than in A. 

 gracilis, being in the Sardinian specimens nearly three times as 

 long and much larger than in our species. In this respect, the 

 genus shows a close affinity to Branchinecta. However, in a lot 

 of A. salina 9 from Trieste, the cercopods are very much shorter 

 than in the Sardinian females, and only a little longer than in 

 our American specimens. These appendages do not ditfer in the 

 two sexes." 



A. S. Packakd, Jun. 



