GENUS ELMINIUS. 347 



crenated. In E. simplex they are extremely narrow, smooth- 

 edged, and rounded : in E. plicatus they are narrow, and in 

 this species alone the sutural edge is sinuous, and sends 

 inwards short ridges or teeth. The alse, in all the species 

 except this last, are likewise smooth-edged. The lower edge 

 of the sheath depends, more or less freely, in all the species, 

 except in E. Kingii. 



Basis, membranous in all four species. In E. modest us, 

 the true basal membrane is extremely thin, and is divided into 

 concentric slips : on its inner surface there are attached 

 numerous cement-ducts, varying from ^ m to ~ of an inch 

 in diameter, repeatedly trifurcating, rarely forming hexagonal 

 or quadrangular loops, and with the branches placed ap- 

 proximately parallel to each other. Beneath the true basal 

 membrane there is a complicated layer of cement, in the 

 form of a net-work, or of separate tubes, or in beads and 

 patches. In E. Kingii, the basal membrane presented a 

 wonderfully complicated appearance, in part due to the 

 cement forming a mass of inosculating fibres; many of 

 these fibres seemed to end in circular discs of cement. 



Neither the Mouth or Cirri offer any noticeable generic 

 characters, as distinct from Balanus and several other genera. 

 The Branchice, in E. plicatus, are well developed and mode- 

 rately plicated. In E. modesties they are small, not 

 plicated, but with a rounded sinuous margin : in a speci- 

 men having a basal diameter of $ s , the branchiae in total 

 length were only -^ of an inch. At the bottom of the sack 

 I observed some inwardly pointed, tapering filaments, such 

 as occur in Balanus. In this same species I measured the 

 ova, which were unusually elongated, being ~% in length ; I 

 may add, that the probosciformed penis was actually thrice 

 the length of the animal's body in some small but mature 

 specimens (with ova), having a shell with a basal diameter 



of ^o of an inch. 



Distribution and Habitats. — This genus is remarkable, in- 

 asmuch as it is not distributed over the whole globe : three 

 of the species occur very commonly on the shores of New 

 South Wales, Van Diemen's Land, and New Zealand ; not 

 extending, as far as I can judge, much north of Sydney : 

 the fourth species is confined to South America, ranging 



