ON FOSSIL CRUSTACEA. 325 



true shore-crabs, their legs being adapted for ruiming, and their eyes 

 furnished with long peduncles* (see Quart. Journ. Geol. Soc. vol. xxix. 

 p. 28). 



This series of Crustacea (though they are exceedingly brittle and delicate) 

 are remarkable for the perfect state of preservation in which they occur, so 

 that we are able in each case to restore nearly the entire animal. Of the 

 two new ones, it is interesting to record that they afford evidence of unmis- 

 takable land conditions, both of them being shore-dwellers and adapted for 

 running on the old muddy and sandy beaches of the pre-Eocene continent. 

 The sections still, I believe, open at Portsmouth deserve an inspection from 

 all who are interested in the stratigraphical geology of this series of deposits. 



Miocene Crustacea. — Having been requested by Dr. A. Leith Adams, P.E..S., 

 to examine and describe a series of crustacean remains from the Miocene of 

 Malta, collected by him in that island, I have done so, and find them to in- 

 clude Scylla, Baniiia, Portunites, Main, Atergatis, and perhaps Nepiumis. 

 The Scylla agrees specifically wth the Scylla serrata found in the Indian 

 seas of to-day and in the Tertiaries of the Philippine Islands. This is one 

 of the species of fossil crabs so largely imported into China as " Medicine- 

 Crabs " (see Mr. D. Hanbury's papers read before the Pharmaceutical Society, 

 and published in their Journal, Pebruary 1862 et seq.). 



The Eanina is distinct from any recorded species, and I have therefore to 

 propose for it a specific name. I dedicate it to its discoverer {R. Adamsi). 



The occurrence of these Eastern forms, with the remarkable Echinoderms 

 of Asiatic type, in Malta, clearly indicate the former extension of an Indian 

 fauna as far east as the Mediterranean, if not to our own shores. 



Whilst still pursuing the subject of the structure of the Trilobites, no new 

 facts have been collected ; but much has been done in the examination of 

 larval Limulus, the substance of which I have summarized in a paper read 

 in December last before the Geological Society (see Quart. Journ. Geol. Soc. 

 vol. xxviii. p. 46), 



Dr. Anton Dohrn, without (as I think) any very clear reason, proposes to 

 separate the XirnosuEA and the Euetpteeida, and also the Teilobita, from 

 the Crustacea, on the ground that they do not, so far as we are at present 

 aware, pass through aNauplius stage ; but the young are like the parents save 

 in the fewer niimbcr of their somites. He is, however, unprepared to say they 

 are Arachnids, so that he can only place them in a group intermediate between 

 the Arachnida and Crustacea (the Gigantostraka of Hack el). Against this 

 course I have protested on the grounds that if Ave take away the Trilobita from 

 the pedigree of the Crustacea, one of the main arguments in favour of evolution 

 to be derived from this class, so far from being strengthened, is destroyed. 

 From what are the Crustacea of to-day derived ? Are we to assume that they 

 are all descended from the Phyllopods and Ostracods, the only two remaining 

 orders whose life-history is conterminous with that of the Trilobita ? Or are 

 we to assume that the Arachnida are the older class ? " If," as Fritz Miiller 

 well observes, " all the classes of the Arthropoda (Crustacea, Insecta, Myrio- 

 poda, and Arachnida) are indeed all branches of a common stem (and of this 

 there can scarcely be a doubt), it is evident that the water-inhabiting and water- 

 breathing Crustacea must be regarded as the original stem from which the 

 other (terrestrial) classes, with their tracheal respiration, have branched off." 

 (Facts and Arguments for Darwin, p. 120.) 



* Under the name of Gonwcypoda Edwardsii, I desevibed a true Eocene shore-crab 

 from tlie Eed Marl of the Plastic Clay, High Cliff, Hampshire, in December 1867 (see 

 Geol. Mag. vol. iv. p. 529, pi. 21. fig. 1). 



