30 FOSSIL MALACOSTRACOUS CRUSTACEA. 



in a curved line from behind the cardiac region to the posterior lateral spine ; the anterior 

 portion, consisting of the epibranchial and mesobranchial lobes, is somewhat rugous, and 

 bears two tubercles, of which the hinder one is the larger ; the posterior portion, or 

 metabranchial lobe, which is considerably the larger, is everywhere rough, but without 

 tubercles, and that of each side meets the opposite so as to form a peculiar, large, rugous 

 area, occupying the whole breadth of at least the posterior third of the carapace ; the 

 posterior margin is broadly emarginate, and slightly elevated. The pterygostomian 

 processes are deep, tumid, and irregularly mammillated. In all the specimens I have seen, 

 the parts about the antennary and oral regions are too much mutilated to afford any 

 accurate indication of the structure of these parts ; but from the fragments which exist, 

 there is little doubt that they resemble essentially those in the D. Bucldandi. The 

 anterior legs are equal, somewhat longer in proportion than in the other species, being 

 nearly twice as long as the carapace, generally smooth, although less so than in 

 D. Bucldandi. The wrist in the male is one third longer than it is broad ; in other 

 respects the proportions are nearly the same, and the remaining pairs of legs do not differ 

 from it in any important respect. The abdomen in both sexes has all the segments 

 separate ; in the male it is of nearly equal breadth throughout its whole length, with 

 a rounded, longitudinal ridge along the centre, and a sulcus on each side of it, which 

 is also the case with that of the female, in which the segments are more nearly of equal 

 breadth than in D. BucJdandii. The puncta of the surface both of the carapace 

 and members, are no less universal and numerous than in that species, although from the 

 greater roughness of the surface generally, they are much less conspicuous, and in some 

 specimens and parts of others, very difficult to be detected. There can be no doubt, 

 however, that this species, as well as the other, was, like their existing congeners, covered 

 with hair. 



Length of carapace, 1*4 inch ; breadth, 1*2 inch. 



This species is found in considerable abundance in Sheppey, as well as in other parts 

 of the London Clay, particularly about Highgate, near Chalk Farm, &c. It appears to be 

 one of the most generally distributed species found in the London Clay. 



The location of this Crustacean in the genus Inachus by Desmarest, requires no 

 observation. Its true position amongst the Anomura has been already shown by Professor 

 M'Coy, and its generic relation to Dromilites is now, it is hoped, shown to be no 

 less certain. It is an interesting fact, that there existed at the period of the deposit 

 of the Eocene beds, such distinct representatives of one of the most remarkable types 

 of the anomurous decapods, which are, at the same time, unmistakeably distinct in their 

 generic characters. It is also Avorthy of notice, that the species now described shows 

 a certain remote approach to the genus Homola, especially to the deep sea Mediterranean 

 species II. Ciwieri, first described by Roux.* 



* 'Crust, de la Mediter.,' t. vii. 



