148 CEYLON PEARL OYSTER REPORT. 



*Balanus allium, Darwin. 



Locality : Coral reefs off Ceylon. 



Several small specimens on Turhinaria, together with B. terebratus, Acasta funicu- 

 lorum and Pyrgoma conjugatum. Probably they are immature, as the base is nearly 

 flat, although the shell and operculum agree with Darwin's description and figures. 



This Barnacle has been recorded from the Red Sea and from Australia as well as 

 from Ceylon. It is probably another circumtropical species, its small size and incon- 

 spicuous appearance having caused it to be neglected by collectors. 



*Balanus terebratus, Darwin. 



Locality : Coral reefs off Ceylon. 



Several specimens, with those of the preceding species. They agree closely with 

 Borradaile's description (9) as regards the structure of the operculum. Darwin (2), 

 who had examined a single specimen, said regarding it, " the interspaces between the 

 ridges (on the basis) are penetrated by small rounded apertures, of irregular shape 

 and unequal sizes." Borradaile was unable to see these apertures, and they are 

 absent in some examples I have examined. In one individual, however, there appear 

 to be indications that they have been present, but have been almost obliterated during 

 growth. The specimens are small, the antero-posterior diameter of the largest being 

 7 millims., and are apparently more steeply conical than the type. 



*Balanus aeneas, Lanchester (8). 



Locality : Pearl Banks, Gulf of Manaar. 



Numerous small individuals, measuring about 3 millims. in antero-posterior diameter, 

 on a piece of sodden palm fibre, on a shell, and on dead Heteropsammia. 



In spite of their small size these individuals contain eggs inside the shell. The 

 eggs are of a broad ovoid outline, measure IP333 millim. in length and 0'2 millhn. in 

 maximum breadth, and are comparatively few in Dumber. The maxillae have in one 

 specimen only six teeth, the third being represented merely by a short bristle ; while 

 in the other individuals there are seven. 



Loose in the shell of one specimen I found a peculiar little Nematode, the affinities 

 of which I do not venture to decide. 



*Balanus maldivensis, Borradaile (9). 



Locality : Gulf of Manaar. 



Five specimens on a piece of dead coral. Possibly some other very much worn 

 examples, fixed to a dead Heteropsammia, may also belong to this species. The 

 shells are white with vertical stripes of rose-pink. Their coloration gives them 

 a general resemblance to some specimens of B. amphitrite, var. venustus. 



Borradaile's section H of the genus Balanus, created for this form in l'J03, is not 

 the same as Gruvel's section H, which was published for B. dybowskii in the same 



