820 THE AMERICAN NATURALIST. [VOL. XXXIII. 
is replaced by the Palinurids or spring lobsters, and by the 
flattened Scyllarids. These groups are frequently united by 
European carcinologists under the name Loricata. They are 
extremely interesting, on account of the peculiar leaf-like larvae 
(Phyllosoma) which hatch from the eggs. In these the body 
is scarcely thicker than a sheet of this paper, but it may be 
two or three inches in length and half as broad. 
The Thalassinids are marine burrowing forms, living in the 
sand and mud and frequently showing the effects of this life 
in the very soft and membranous integument, the pincers alone 
being hardened in some of these Crustacea. 
The most important papers relating to the description of our 
American species are : — 
MILNE-EDWARDS. Histoire Naturelle des Crustacés. Tomeii. 1837. 
Dana. Crustacea of the United States Exploring Expedition. 1852. 
STIMPSON. Crustacea of Pacific Coast. Journ. Boston Soc. Nat. Hist. 
Vol. vi. 1857. 
HAGEN. Monograph of the North American Astacide. Mem. Mus. Comp. 
Zool. Vol. iii. 1870. 
SMITH. Invertebrates of Vineyard Sound. Rep. U. S. Fish Commission 
for 1871-72. 
SMITH. Preliminary Notice of Crustacea [etc.]. Proc. U.S. Nat. Mus. 
Vol. iii. 1881. 
RANDALL. Catalogue of Crustacea [etc.]. Journ. Acad. Nat. Sct. Phila- 
delphia. Vol. viii. 1839. 
STIMPSON. Notes on North American Crustacea. Annals N. Y. Lyc. Nat. 
fist. © Vol. x Y67%. 
GIBBES. Proc. Am. Assoc. Adv. Sct. Vol. iii, pp. 192-195. 1851. 
KINGSLEY. Bull. Essex Inst. Vol. xxvii, p. 95. 1897. Vol. xiv, p. 131. 
Faxon. A Revision of the Astacide. Bull. Mus. Comp. Zoöl. Vol. x. 1885. 
KEY TO ASTACOID AND THALASSINOID CRUSTACEA OF THE 
UNITED STATES. 
— 
. Macrura (see Am. Nat., vol. xxxiii, p. 708) : 2 
Carapax with two longitudinal sutures ; cervical suture e frequently pres- 
ent; antennal scale small or wanting. . Thalassinoidea 12 
Carapax without longitudinal sutures ; cervical suture frequently pres- 
ent; antennal scale small or obsolete Astacoidea 3 
arapax without sutures; antennal scale iaa Cirk (see p. 713). 
Antennal scale usually present; anterior feet chelate; body sub-cylin- 
drical; abdomen large . ; ; . ‘ Astacide 4 
p 
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