Henry Woodward — Fossil Crab from Mekran Coast. 309 



In Neptunns (Amphitnte) gladiator, Fabr. (De Haan, tab. i, fig. 5), 

 the general features resemble our Mekran crab, but the regions of 

 the carapace do not correspond in detail ; the costal spines, although 

 not so long as in A. hastatoides, are not straight but curved some- 

 what forward ; the frontal border between the orbits has six distinct 

 pointed teeth, not four rounded double prominences as in our 

 specimen. The branchial furrow in A. gladiator also is much more 

 arcuate. 



On the whole, I find that Neptunns {AmpUtrite) tenuipes, De Haan 

 (tab. i, fig. 3), agrees most nearly with our Mekran crab. The 

 costal spines are not dissimilar in length ; the regions of the carapace 

 resemble the fossil in most particulars. We are unable to compare 

 the maxillipeds in our specimen with De Haan's figures, as we have 

 only the dorsal aspect of the carapace exposed in the nodule. 



The frontal region does not exhibit quite the same rounded and 

 paired undulations as in our fossil crab, nor are the costal spines of 

 equal proportion. 



I prefer, therefore, to designate the fossil form from Mekran by 

 the trivial name of N. Arabicus, in allusion to the Ai-abian Sea, which 

 washes the shores of the Ormara Headland, where these concretions 

 were collected. 



Before quitting this subject, I may refer to another allied fossil 

 crab with long costal spines, described by me as RhacMospma 

 bispinosa, of which a fine series of specimens was obtained by the 

 late Messrs. 0. J. A. Meyer and Caleb Evans from the Lower Eocene 

 of Portsmouth Dockyard (and figured and described by me in the 

 Quart. Journ. Geol. Soc, 1870, vol. xxvii, pp. 90-92, pi. iv, figs. 3, 5 ; 

 and 1873, vol. xxix. pp. 25-31, doul)le-plate i, figs. 1-6). These 

 specimems are of extreme interest in connection with the evolution 

 of this group of the Brachyura, as they present a more generalized 

 form, combining the character of the Neptunidse in the development 

 of the strong costal spine, not produced in the Portunid^, but 

 agreeing with the latter in having only five spines or serrations on 

 the latero-anterior border instead of nine, as in Neptunns (see op. cit., 

 1873, vol. xxix, pi. i, in which the latest and most perfect examples 

 are figured). These beautiful specimens from the Lower Eocene 

 are preserved in the Museum of the Geological Society, Burlington 

 House, a bequest from the late Mr. Caleb Evans, F.G.S. 



Should other and more perfect specimens from the Mekran Coast 

 be met with, and prove to have only five serrations on the latero- 

 anterior margin, then this form might be generically separated from 

 Neptunus 3ind form, with Rhachiosoma, another subfamily intermediate 

 between the Portunidse and the Neptunidse, as combining some of 

 the characters found in both these groups. 



Note on Balanus tusttinxabctlum, Linn. 



Darwin's var. 7, coccopoma: " Cirripedia: Balanidse," Ray Society, 1854, 

 pp. 194-196, pi. i, figs. 1, 2. 



The Balani from Ormara Headland, Mekran Coast, are contained in 

 two nodules, one of which exhibits two or three examples only, the 



