442 



L. A. BORRADAILE. 



8. Balanus quadrivittatus Darw., 1854. Darwin, II. p. 284. 

 Taken in Miladumadulu Atoll. 



9. 1 Balanus terehratus Darw., 1854. Darwin, II. p. 288. 



I am unable to find in my specimens the rows of holes between the ridges of the 

 basis as described by Darwin. Possibly the species is distinct. The scuta and terga, which 

 were wanting in Darwin's specimens, have the following characters in mine: 



Scuta. Shape that of a right-angled triangle with convex base. Growth ridges on the 

 outside curved. Adductor ridge strong and articular moderate. 



Terga. Spur very short and fairly broad. Growth ridges on the outside curved. Spur 

 groove wide, shallow. Apical tooth present, but broken in the specimen. 



Taken on the reef at Naifaro, Fadifolu Atoll. 



10. Balanus maldivensis n. sp. (Fig. 118). 



Diagnosis : " A Balanus with solid walls, the basis, radii and parietes being without 

 canals, though indications of these are seen in 

 the parietes when the latter are broken ; the 

 opening rhomboidal, and toothed owing to the 

 projection of the tips of the parietes, the walls 

 gnarled and often ringed, but not regularly 

 ribbed ; the scutum of simple, obtuse-angled tri- 

 angular shape, with slight articular and no 

 adductor ridge ; the tergum very broad with a 

 rounded tip, a short, broad spur, which is also 

 rounded at the end, a sharp tooth at the end 

 of the scutal edge next the spur, and a shai-p, 

 though not very deep, spur groove ; the outside 

 of both scutum and tergum moderately strongly 

 ridged ; the mandible with seven teeth, which 



grow smaller in succession from above downwards, and of which numbers 1 — 5 are blunt 

 and often subdivided, while 6 and 7 are sharp, a row of stiff bristles along the lower 

 edge and the sides and upper edge hairy; and the edge of the maxilla almost straight, 

 without notch or projection." 



Length of longest specimen : 7 mm. Height : 6 mm. 



Taken in S. Nilandu Atoll, on a twig of wood. 



The peculiarities of the shell of this species would appear to necessitate the founding 

 for it of a new section [H] of the genus, with the characters : " All parts of the shell 

 present, heavy, and without pores." 



Fio. 118. Balanus maldivensis ; whole animal, with 

 scutum and tergum detached and seen from the inside. 



Genus Acasta Leach, 1817. 



11. Acasta sulcata Lam., 1818. Darwin, ii. p. 310. 

 Dredged in two fathoms in Fadifolu Atoll. 



