690 L. A. BORRADAILE. 
26. Lambrus (Rhinolambrus) gracilis Dana, 1852. Alcock, 1. p. 269. 
The specimens which I assign to this species agree with Alcock’s description fully, 
except that the surface of the carapace is not absolutely smooth, there being several granules 
round the cardiac spine and along the branchial ridges. 
Dredged in Felidu, Fadifolu and Suvadiva Atolls, in 22—43 fathoms. 
27. Lambrus (Rhinolambrus) turriger Ad. and Wh., 1847, Alcock, 1. p. 269 (Pl. XLVII. 
fig. 5). 
Dredged in South Nilandu, Felidu, Mulaku, Haddumati, Suvadiva, Kolumadulu and 
North Male Atolls, in 25—42 fathoms. 
28. Lambrus (Aulacolambrus) sculptus A. M.-Edw., 1872. Alcock, 1. p. 272 (Pl. XLVII. 
fig. 6). 
Dredged in South Nilandu, Felidu, Mulaku, and Suvadiva Atolls, in 20—43 fathoms. 
29. Lambrus (Parthenolambrus) calappoides Ad. and Wh., 1847. Alcock, I. p. 275, 
Dredged in South Nilandu and Suvadiva in 36 and 35 fathoms respectively. 
XI. ON THE CLASSIFICATION AND GENEALOGY OF THE 
REPTANT DECAPODS. 
Besides the brachyurous Crabs, Boas’ Reptantia’ comprised sundry groups which are not 
brachyurous, that is have a pair of biramous limbs on the sixth segment of the abdomen, 
which bears traces of adaptation to other purposes than reproduction, such as swimming 
or holding on a shell, and have also no fusion between the rostrum or front and the 
epistome and no angle on the endopodite of the first maxilliped. The following are the 
names of these groups: Eryonidea, Scyllaridea (= Loricata), Nephropsidea (= Homaridea and 
Astacidea), Thalassinidea, Paguridea, Galatheidea, and Hippidea, the last three being together 
known as Anomala by Boas and most other writers. 
Our present object is to arrange these divisions according to their relationships, and to 
do this we must first of all form an idea of the ancestor from which they may be supposed 
to be descended. More space would be needed than can be spared here to set forth in 
detail the process of comparison of the various types with one another and with the prawns 
of the Stenopidea and Penaeidea, by which this result may be reached, and indeed this 
might after all be hardly worth while, for the following statement will, I think, commend 
itself to those who have studied the subject as on the whole probable. 
The forebears of the reptant Decapods, if they could be examined, would probably show 
the following characters : 
(1) The rostrum of a good size, flat but keeled, and narrowly triangular. 
(2) The carapace subcylindrical, free from the epistome both at the sides and in the middle, 
overlapped behind by a process of the first abdominal segment on each side, and marked by the 
following grooves: on the back two running transversely (the first, line e of Boas, is Bouvier’s 
1 See above, Art. 1v. vol. 1. p. 424, 
