14 AMI'IIIPODA XOltMAT.IA. 



and not concave, nor cmarginate, not toothed, but set with 

 spinules ; finger long, carpus very transverse, third joint rectan- 

 gular, a little oblong, naked. 

 '' Length six lines. 



"Hah. Rio Janeiro ; dredged in the hai-bour." (Dann.) 



7. Orchestoidea Calif oniiana. 



Megalorchestia Californiana, Brandt, BiiUctin Physico-Math^matique 

 de r Acad, de St. Petershourg, ix. 311. 



Stimpson, Journ. Bost. Soc. Nat. Hist. vol. vi. 



I have not seen either the animal or Brandt's description ; I there- 

 fore give the following from Mr. Stimpson's memoir '• On the Crus- 

 tacea and Echinodermata of the Pacific Shores of America," pub- 

 lished in the ' Journal of the Boston Society of Xatui-al Historj',' 

 vol. vi. : — 



"■ This differs from 0. scahrlpes, among other characters, in the 

 great length of the fifth epimeral '' (coxa of the thii'd pereiopod), 

 " and in ha\-ing the outer branch of the fii'st pair* of caudal stylets 

 equally spinulose with the inner one. The feet are not scabrous, 

 while the antemise are so on a considerable portion of their surface." 



"Hah. Bogeda (Wonesseml-i) ; Monterey (Trt!/ /or)." 



3. TALORCHESTIA, Dana. 



This genus differs from Talitrus in having the first pair of gna- 

 thopoda subchcKform in the male, as in Orchestia, and the second 

 developed largely, as in the male of Orchestoidea and Orchestia, 

 whereas in the female the first giiathopoda are simple, as in Tali- 

 trvs, and the second feeble and unimportant, as in the normal 

 Talitri. 



This genus was founded by Dana for certain species that Fr. 

 Midler fii'st discovered, the males of which were true Orchestice, 

 whereas the females were perfect Talitri. This cii'cumstance Prof. 

 Dana having corroborated, induced him to divide the group which 

 Midler had united into the genus Orcliestia, into tlu'ee equal sub- 

 genera, viz. Talitrus, Talorchestia, and Orchestia, — the first being 

 true Talitri ; the second were Talitri in the males, and Orchestice in 

 the females ; and the third were true Orchestia'. This arrangement 

 was followed by myself in the S}Tiopsis of the British Ediiophthal- 

 mia ; but I have thought, since I foimd that Nicolet, Brandt, and 

 Stimpson had diATided the genus Talitrus into two genera, viz. 

 Talitrus and Orchestoidea, that the arrangement now given is more 

 in accordance with natiu'e than the adoption of subgenenc groups, 

 which T am inclined to think should be as much as possible avoided 

 in classification. 



