20 



following trunk legs are more or less dorsally carinate, the 

 ridge seeming to be sharpest on the fifth joint. The fingers 

 are spinulose on the concave margin as far as the nail, which 

 is horny-looking and smooth. 



Krauss describes and figures Acanthonyx macleayii as 

 without a tooth at the outer angle of the ophthalmic orbit 

 and as having the two lateral teeth of the carapace widely 

 distant, and AciDithonyx qitadridcntatus with four teeth on 

 each side of the carapace. Miers retains these in the genus 

 Acanthonyx, although they both have a seven-jointed pleon, 

 which appears to be the chief, if not the only, distinction 

 of DeJiaanius from AcanfJioiiyx. A question remains open 

 whether these two species may not be mere variations of 

 Dehamihis dentatus. Krauss reports them all from the rocky 

 coasts of Natal, describing Macleayii as dull reddish-brown, 

 7 lines long; dentatus as red-brown, ^i-^ lines; qiiadridentattcs 

 yellowish-brown, 5.7 lines. The specimens from Algoa Bay, 

 dredged between Bird Island and the mainland, at a depth 

 of 10-16 fathoms, on a bottom of sand and shells and stones, 

 were of various sizes, the largest nearly 1 1 lines long from 

 tips of rostrum to hind margin of carapace. They also vary 

 much in colour markings, one of the largest being all over of 

 a lively red, except for a dot of white near the middle of the 

 carapace, and another near the end of the pleon, and the tips 

 and teeth of the fingers, which are yellowish. Another large 

 specimen has two white blotches above and several below. 

 Some of the specimens are marbled with red and white, one 

 or the other being more predominant, in one specimen the 

 red almost disappearing, so as to leave a yellowish-brown 

 effect. 



All the specimens were more or less coated with algae, 

 hydroid zoophytes, and other foreign substances, among 

 which in one instance a small amphipod was found nestling. 

 The extraneous organisms were principally attached near the 

 rostrum, but in many cases the whole external surface of the 

 body, including the third maxillipeds and the pleon, is coated 

 with outgrowths such as those described by Dr. Graeffe for 

 Pisa armata (Bolletino Soc. adriatica sci. nat. in Trieste, vol. 7, 

 1882), and by Sars for ^^ Scyramathia Carpenter i" (1885). 

 Besides the tubules of different lengths with thickened ends, 

 on the projecting point in the sixth joint of the walking-legs 

 there are groups which differ from the others in having acute 

 apices. Almost everywhere are found outgrowths which are 

 short, broad, and flattened. To these the midrib, which is 

 common to all, gives a leaf-like appearance, but their normal 

 condition appears to be not flattened but inflated, and they 

 are perhaps essentially the same in structure as the tubules. 



