October 26, 1S83.] 



SCIENCE. 



571 



PACKARD'S PHYLLOron CRUSTACEA. 



A »innoffra/ih of the plii/llnpnd Crtislaccn of Nurlh 

 America, with reiiinrks un the oriler J'hi/llncaru/a. 

 By A. S. Packakd, Jun. Autlior's edition, 

 extracted from the twelfth annual report of 

 the U. S. geolos;ical and geographical survey. 

 Washington, iniii. 298 p., 39 pi., map. 8°. 



ALTnoLt;ii Professor Packard began publish- 

 ing upon the Piiylloiwda long ago, and has for 

 several jears been well known to be engaged 

 upon a monograph of the North-American spe- 

 cies, the bulk of the work just published, and 

 the i)rofusion of its illustrations, are a great 

 surprise. It is the most extensive, and in 

 many ways the most important, monographic 

 contribution to American carcinology : and, 

 however we may criticise the execution of the 

 work, ever\- student of the American fauna 

 must feel grateful to the author for undertak- 

 ing and acconi[)lishing it. 



The work is much more than a systematic 

 monograph of North-American Pliyllo|joda, 

 as the following table of contents will show: 

 1. Classification of the living Phyllopoda, 

 which includes the systematic description of 

 the North-American species; II. Geological 

 succession, including descriptions of the North- 

 American fossil species; III. Geographical 

 distril)utioii ; IV. Morphology and anatomy ; 

 V. Development, metamorphoses, and gene- 

 alogy; VI. Miscellaneous notes on the repro- 

 ductive haliits of Branchipodidae, by Carl F. 

 Gissler; VII. The order Phyllocarida, and its 

 systematic position ; VIII. IJibliography ; Ap- 

 pendi.x, consisting of translations or abstracts 

 by Gissler, of papers by C. T. von Siebold, 

 on Arteniia ferlilis from Great Salt Lake, and 

 on parthenogenesis in Artemia salina ; and 1)3' 

 Schraankewitsch, on the relation of Artemia 

 salina to Artemia Muehliiausenii and to the 

 genus IJranchipus, and on tiie influence of ex- 

 ternal conditions of life uijon the organization 

 of animals. There is some confusion between 

 the lilies of the principal divisions, which arc 

 given above, and the table of contents in the 

 work itself. Scarce!}' any of the titles are the 

 same : and, in place of ' Miscellaneous notes 

 on the re|)roductive habits of Branchipodidae,' 

 we have, in the table of contents, ' Relation 

 to their environment; liabits,' — subjects no- 

 where treated under a separate heading ; and 

 all reference to the long appendix is omitted. 



About a fourth of the entire work is devoted 

 to the systematic account of the species and 

 higher groups of Phyllopoda, regarded by Pro- 

 fessor Packard as a sub-order of Branchiopoda, 

 which is made to include C'ladocera and Ostra- 

 coda also. The Pliyllo[)oda are divided as 



follows into families and sub-families, which 

 include the numl)er of recognized North- 

 American genera and species uearl}' as indi- 

 cated : — 



Ll.MXADIIDAE : 



Linnietin.ae (1 genus, 4 species). 

 P^stheriinac (3 genera, 11 species). 

 AroDiDAi; (2 genera, 9 species). 



BUANCIIII'OIUOAE : 



Branchipodinae (5 genera, 12 species). 

 Thamnocephalinae (1 genus, 1 species). 



All the groups are described ; nearly all the 

 species are figured, many of them very fully ; 

 and important notes on variabilit}- and habits 

 are given for some of the species. Arteniia 

 gracilis is treated more at length than any 

 other species, and is made to include all the 

 described North-American species ; but, in re- 

 gard to its relation to the European A. salina, 

 tiiere is certainly confusion, as the following 

 paragraphs show. 



" Upon comparing our species with the Eu- 

 ropean, it is difficult to find good differential 

 ciiaracters, as the portions of the body where 

 specific differences woukl be expected to occur 

 are liable to considerable variation. Ujjon 

 comparing a number of females from Great 

 Salt Lake with a number of females of the 

 maleless generation from Trieste, Austria, 

 received from Professor Siebold, there are 

 really no difl'erences of importance. Our A. 

 gracilis (Verrill's fertilis) is slighter, with a 

 smaller head ; and perhaps the second antennae 

 are a little slighter in build ; I see no essen- 

 tial difference in the form of the ovisac, while 

 the shape of the legs, especially the sixth cu- 

 dite, is essentially the same " (p. 331). 



" On comparing a number of Salt Lake fe- 

 males with individuals of the same sex of the 

 European Artemia salina, our species was 

 found to be undoubtedly specifically distinct ; 

 the Utah specimens are slenderer, smaller, and 

 the sixth enditc of all the feet considerably 

 slenderer and longer in proportion than in A. 

 salina. The ovisacs were of the same propor- 

 tion but slenderer, and the head is slighter and 

 smaller in our American species " (p. 333). 



Different conclusions on neighl)oring pages, 

 in regard to the specific identity of closely allied 

 forms, might be accounted for in' a careless 

 author ; but differences like these in statements 

 of observation betray inexplicable careless- 

 ness. 



In the chapter on geological succession, a 

 table of the geological and geographical distri- 

 liution of the known fossil species is given, and 

 also a diagram indicating the geological his- 



