886 PROF. S. J. JlICKSON^ ON THE 



of measurement for comparison. Taking the measurement of a 

 few of the projections at a distance of about 3 mm. from the apex 

 of the branches, I have found that the average is in " Benhami " 

 0*7 mm., and in " Dendyi " 0'4 mm., the pi"OJections in "Ramosa " 

 and " Oooki " being intermediate in size between these two 

 measurements. The differences between these averages are so 

 small, and the difficulty of avoiding a relatively large error in the 

 calculation is so great, that the measurements are of no more 

 scientific value than to express roughly the general impression of 

 observation that the projections are longest in " Benhami," 

 shortest in " Dendyi," and of medium length in other specimens. 

 The longest projections in "Benhami" are, however, not simple 

 nariform processes as they are usually in the other facies, but 

 groups of two, three or four of these processes clustered together 

 (fig. 13). The clustering together of the grooved projections 

 may be seen in some of the other facies, such as " Ramosa " and 

 " Oooki, ' but it is never such a pronounced feature as it is in 

 " Benhami." 



Lastly, a word about geographical distribution. All the 

 specimens were dredged off the coast of New Zealand, and two of 

 these four were found in the same bay (Preservation Inlet). 

 There is every reason to believe, moreover, that they were all 

 found in shallow water. In my opinion these facts have some 

 weight in determining the question whether the specimens 

 should be placed in one species or in several species. In a rare 

 genus such as Errina, species found at widely separated localities 

 will in all probability be affected by their isolation and show 

 differences that entitle them to rank as distinct species, but 

 there is much less probability that the genus would be able to 

 develop or to maintain specific differences in the same waters. 

 Unless, therefore, a very clear case is made out that the dif- 

 ferences between the specimens of the genus Errina from New 

 Zealand waters are constant or of fundamental importance, the 

 most convenient as well as most scientific course to pursue is to 

 place them together in the same species. 



Errina (Labiopora) capensis, sp. n. (PI. XCY. fig. 7 ; 

 PI. XCVI. fig. 15.) 



This species is represented in my collection by three broken 

 terminal branches. The largest piece is 36 mm. in length, the 

 diameter at the base is 7 mm., and the diameter of the branch 

 8 mm. from the apex is 4*5 mm. In the largest specimen of 

 the New Zealand species ("Dendyi") the diameter at the base 

 (evidently the base of attachment) is 6 mm., and the diameter of 

 a branch 3 mm. from the apex is only 2 mm. 



From these facts it seems probable that in this species the 

 hydrophytum reaches to much greater dimensions than does that 

 of the New Zealand species. 



The branches terminate in blunt, slightly flattened and ex- 

 panded extremities. 



