328 A. E. Verrill — Decapod Crustacea of Bermuda. 



This is one of the most common species, taken by nearly all col- 

 lectors in Bermuda. It is often seen running actively about among 

 the stones and dead seaweeds, from low tide nearly to high -water 

 mark, usually associated with Pachygrapsus transversus. It may 

 almost always be found under masses of Sargassum cast up on the 

 shores as well as under stones. 



Its range extends from Florida through the West Indies to 

 Trinidad. 



Sesarma Ricordi, var. terrestris, subspecies or var. nov. 



Plate XI, Figure 3. 



Tiiis form first attracted my attention on account of its peculiar 

 habits. Unlike most Sesarmce, it lives awa}^ from the water, often 

 in very dry, barren, sandy fields or pastures, under stones, though it 

 was also found not far from the shore but where the soil was dry. 

 It runs very rapidly when disturbed, and hides in holes or under 

 other stones, but does not seek the water. Its color was darker than 

 in the ordinary form, and the carapace was usually more or less cov- 

 ered by short hairs and adherent dirt, obscuring the colors, and giving 

 it a gray appearance. Although so different in appearance and 

 habits, it agrees so closely in form and structure that it seems to be 

 only a variety that has acquired terrestrial habits, with trivial 

 changes adapting it better for this mode of life.* But no really 

 intermediate specimens were found. Thus it seems to be a form or 

 subspecies of some considerable antiquity and constancy. 



The carapace appears more rough and uneven than in the ordinary 

 form, for it is more strongly areolated and the branchial areas are 

 more swollen, so that the vertical thickness is greater and the reticu- 

 lated areas of the sides are broader, giving a larger surface for 

 aeration of the water, and indicating larger gill cavities and gills. 

 The dorsal surface of the carapace is covered with more numerous 

 and larger granules, bearing numerous short dark hairs, very evident 

 under a lens of low power, and capable of holding adherent dirt : 

 the plicae on the postero-lateral sides are stronger and more granu- 

 lous ; the lateral marginal edge is more sinuous anteriorly, owing to 

 the more swollen branchial chamber. The anterior frontal margin 

 is less sinuous, the median indentation often being obsolete or faint. 



* The specimens have also been studied by Miss M. J. Eathbun, who agrees 

 with me in its relations. 



