BRACHYURA. 401 



sculpture of its hands and fingers, between E. melissa and E. sculptilis. It differs 

 from tonus hitherto described in: (I) Ratio of C.b. -r- CI. ; (2) the more produced 

 frontal lobes (see figure) : (3) the anterolateral border of the carapace has only four 

 tubercles. The latter point is useful for purposes of key. The anterior of the 

 antero-lateral teeth seems to take the place of the first two antero-lateral tubercles 

 of E. melissa or of E. sculptilis and of a third tubercle to the inner side of these on 

 the dorsal surface of the carapace, which is distinct in both the species named. 

 Correlated with this arrangement is the more regular curve made bv the front and 

 the antero-lateral borders. 



The form of the front is not unlike that of a specimen of Hypocolpus rugosus in the 

 British Museum, in which, moreover, there are only four indistinct lobes on the antero- 

 lateral border. There is a faint depression on the ventral surface behind the orbit 

 and to inner side of 1st antero-lateral tooth. This does not represent the curious deep 

 cavity found in Hypocolpus, for both are present in H. sculptus (i.e., in British Museum 

 specimen from Mauritius 84.8). 



Hypocolpus [= Hypocoelus] rugosus, Henderson, 1893 A.3, p. 111. 



Locality : Coral reef, Gulf of Manaar, two specimens (ovigerous ? and adult <S ). 



I note (1) granules of carapace are larger than in a specimen of H. granulatus in 

 the British Museum instead of smaller as in Henderson's description; (2) the three 

 teeth of the antero-lateral border of the carapace are not so obvious as in Henderson's 

 figure, and in the adult 6 (b) an additional small tooth occurs between the 2nd and 

 3rd larger ones counting from before backwards. In the adult ? (a) there is a mere 

 trace of this additional tooth. 



A point of difference between the present specimen of H. rugosus and the British 

 Museum specimen of H. granulatus is that in the former the sternal area on either 

 side of the flexed abdomen has an eroded appearance, while in the latter it is covered 

 irregularly by distinct granules. 



Xantho distinguendus, de Ha an, 1835 A.3, p. 113. 



Localities : Coral reefs, Gulf of Manaar, one specimen (a) ; south of Galle, deep 

 water, three specimens (b, c, d). 



Description: Specimen (a) is an adult male, C.l. = 6 - 0; specimens (c) and (d) are 

 non-ovigerous adult females; specimen (b) is male, with a parasitic Sacculina. 



Remarks. On comparing with de Haan's example, one notes (l) the much smaller 

 size, and (2) that the posterior surface of the meropodite of the walking leg 4 is smooth 

 instead of granulated. They thus tend to agree with Miers' " Challenger" specimens 

 which he called Lophozozymus bellus, var. leucomanus, but are still smaller. This 

 species is the L. (Lophoxanthus) leucomanus of Lanchester. The Sacculina attached 

 to the male specimen (6) does not seem to have afiected the sexual characters of its 

 host ; the male appendages and the general shape of the abdomen are much as in 

 specimen (a), and no abdominal appendages appropriate to the female are developed. 



3 P 



