92 
THE VOYAGE OF H.M.S. CHALLENGER. 
Stimpson. The post-abdomen, in the male, covers the sternum at the base between the 
fifth pair of legs, and is five or six-jointed, with two or three of the intermediate 
segments coalescent. Eyes short, robust. Antennules usually obliquely plicated, with 
the basal joint considerably developed. The basal (or real second) joint of the antennae is 
short, not markedly dilated, and does not reach the front ; the next joint occupies the 
interior hiatus of the orbit. The exterior maxillipedes present nothing remarkable ; the 
ischium is not produced at its antero-internal angle ; the merus is distally truncated 
and bears the next joint at its antero-internal angle, and the exognath is slender and 
straight. Chelipedes (in the male) subequal and either very considerably elongated 
(typical Lambrus), or of moderate length (subgenus Parthenopoides, Miers); the merus and 
palm are elongated and usually spinose or tuberculated ; palm trigonous, and armed with 
a denticulated or spinose crest along the superior and internal margin ; fingers short, 
distally acute, and dentated on the internal margins. Ambulatory legs slender and of 
moderate length, with the merus-joints sometimes denticulated or tuberculated on the 
margins ; dactyli styliform. 
The species of this genus are very numerous and are probably found in all the 
warmer temperate and tropical seas of the globe, usually in shallow, but sometimes in 
deeper water. 
They have recently been subdivided by Dr. A. Milne Edwards into ten genera. 1 
Of these genera, one, two, or perhaps three ( Rhinolambrus , A Milne Edwards, 
Platylambrus, A. Milne Edwards, and Leiolambrus, A. Milne Edwards), I think are 
insufficiently characterized ; a fourth, Parthenolambrus, A. Milne Edwards, corresponds 
nearly to my Parthenopoides, established in 1879 (when I had not seen the work of A. 
Milne Edwards). Four of the remaining genera (i.e., Solenolambrus, Stimpson, 
Mesorhcea, Stimpson, Enoplolambrus, A. Milne Edwards, and Pisolambrus, A. Milne 
Edwards), are not represented in the Challenger collection. 
Since Dr. A. Milne Edwards has not indicated with anything like completeness the 
species which are to be referred to the subgenera established by him, I give below lists, 
as complete as I can make them, of the species referable to the subgenera represented in 
the collection of H.M.S. Challenger. 
Subgenus Lambrus, A. Milne Edwards. 
Lambrus, A. Milne Edwards (subgen.) Crust, in Miss. Sci. au Mexique, pt. 5, p. 146, 1878. 
„ Miers, Journ. Linn. Soc. Lond., tom. cit., p. 672, 1879. 
Platylambrus, Stimpson (part), Bull. Mus. Comp. Zool., vol. ii. p. 129, 1870. 
Rhinolambrus, A. Milne Edwards, (part), Crust, in Miss. Sci. au Mexique, pt. 5, p. 148, 1878. 
Carapace moderately convex, and not produced over the bases of the legs, rarely 
depressed, with the rostrum and epistoma well developed, the lateral epibranchial spine 
1 Crust, in Miss. Sci. au Mexique, pt. 5, p. 146, 1878. 
