¥817.] Hist. Nat. des Crustacees de Nice. 994 
when they exist. He considers them as constituting a class of the 
type Mottusca. They have no distinct head; they are herma- 
phrodite. Their external covering is soft, and distinctly organized, 
with a branchial and anal opening. The organs of respiration 
occupy the whole or a part of the membranaceous cavity, and are 
attached to the internal surface of the external covering. Their 
mouth is placed at the bottom of the respiratory cavity between the 
two branchiz, and is furnished with labial tentacula. 
This work is concluded with a systematic distribution of these 
animals into 14 genera, with descriptions of the species, elucidated 
by 24 highly finished plates, exhibiting their external and internal 
structure, — 
—S—— 
Il. Histoire Naturelle des Crustacées des Environs de Nice. Par A, 
Risso. Ornée de Gravures. Paris, 1816, 
In this work, which we have just received, the author has ar- 
ranged the crustacea into two orders: 1. Cryptobranches, those with 
concealed organs of respiration. 2. Gymnolranches, those having 
naked or unprotected branchiz. 
The first order contains two sections: I. BRACHYARES, crus- 
tacea with short and naked tails. Family, 1. Cancerides. 2. Oxy- 
rinques. Il. Macrourss, crustacea with a long tail, furnished 
with ciliz, hooks, or swimming plates. Family, 1. Paguriens. 
2. Langoustins. 3. Homardiens. 
The second order comprehends three sections: I. SQuILLINEs, 
head distinct. Family, 1. Squillares. 2. Crevettines. IL, Terra 
CEREs, tail generally with foliaceous plates beneath, Family, 
1, Asellotes. 2. Cloportides. II. Enromostraces, with their 
head soldered to their bodies, Family, 1. Clypéacés. 2. Ostra- 
codes. 
He describes 132 species, which he has distributed into 53 
genera, of which the following are the most interesting or new. 
Gen. Anceus. Thorax quadrate ; mandibules very long, falciform 
and denticulated ; tail furnished with three swimming plates. 
Sp. Forticularius, pl. 2, f. 10. This animal has long been known 
to British naturalists. It was first described by Montagu in the 
seventh volume of the Trans. Linn. Soc, 65, pl. 6, f. 2, under the 
name of cancer maxillaris; but neither Montagu nor Risso has 
been acquainted with its characters. The tail, in fact, has five 
swimming plates at its extremity; and, notwithstanding its sessile 
eyes, it is associated along with the paguriens by Risso, who informs 
us that he has so AM, it on account of its instinct, which re= 
sembles that of the genus hippa, and other paguriens with adactyle 
hands. It inhabits the interstices of madrepores. It is the gnathia 
termitoides of the Edinburgh Encyclopedia, vol. vii. p. 402. 
_ A curious animal is described ‘under the title galathea glabra, 
P. 72, and a fossil species, galathea antiqua, p. 73. 
P 2 
