Botany and Zoology. 121 
the palpus is long and 3-jointed ; if united for some distance up, the 
palpus becomes short and finally only 2-jointed i ti ;) if united 
nearly or quite to their summits, there is no pa 
In the a ngement of the genera into families, the fact whether the 
Ist or 2d ipair of legs s is. the stouler, is here of great weight, muc 
ie: has been recognized. By regarding this character, we are 
to place Hippolyte and Rhyncocinetes with Alpheus, instead of with 
Pa lemon : 3; also ymenocera and Pontonia with Palemon, instead of 
with Alpheus. 
In the preceding : paragraphs we have but hinted at some of the more 
prominent principles involved in the classification of the Macroura here 
presented, a fuller exposition of which will be given in another place. 
elow is a synopsis of the families and sub- families thus arrived at, 
Witha feecoten of the new genera. . 
Synopsis Familiarum Crustaceorum Macrourorum. 
Subtribus I. THALASSINIDEA, vel MACROURA PAGURO- 
: ICA. 
Ca arapax sutura transversa notatus, posticeque sepe suturis duabus 
longitudinalibus. Abdomen seepius multo elongatum. Antenne ex- 
terne squamé basali sive nulla sive parvula instructe. Pedes 2 antici 
Prorsum projecti ; 6 postici habitu raro consimiles. Species fossores. 
Legio I. THALASSINIDEA EUBRANCHIATA. 
Branchiis j instructa thoracicis fantum. 
Fam. 3. THaLa SsINiD £,—Maxillipedes externi peiformes. price 
dices ONC lineares.—Genus : Thalassina, Lat 
Legio I. THALASSINIDEA ANOMOBRANCHIATA. 
Genera :—Callianidea, Edw., Callisea, (Guerin,) D. 
Subtribus II. ASTACIDEA vel MACROURA SUPERIORA. . 
Carapax Sutura transversa sepius notatus, lateribus anterioribus epis- 
tomate connatis. Antennie extern@ squama basali sive nulla sive 
* In our genus Pal the palpus of he mandible is 2- jointed, and in An- 
istia, which is dbealy tee Fae es, b fie in some of rac, pag ere is no 
ple nthe Poti the transition to the Po —. 
, us and CEdipus (Pontonia of authors) fill ad in- 
They are all similar in ving the 
The genera of li vii apne only are mentioned. 
Szoonp Szars, 16 
Vol. XIV, No. 40.—July, 1852. 
