400 PROF. J. A. THOMSON AND MR. W. D. HENDERSO^r ON [Apr. 10^ 



(c) To G. gracilis May we have referred a colony with pinnules 

 in three rows as May described, and to the same species we have 

 referred another colony with only one row. This seemed at first 

 unjustifiable till we saw that in the colony with three rows in the 

 majority some polyps only showed two rows, while in the colonj^ 

 with one row in the majority some showed two rows. 



id) The total number of pinnules seems to us of more diagnostic 

 importance than the number of rows, but in what we believe to 

 be C. garcice we find in one colony a range from 16-30 pairs. 



(e) Comparisons of different colonies of the same species show 

 that there is little use attaching much importance to the length 

 and breadth of the bare streak on the tentacles ixnless one is sure 

 that the forms compared ai'e similarly preserved and in similar 

 states of extension. 



{/) Cases like that which we have for purposes of convenience 

 called C. garcice, var. inermis, lead us to agree with Prof. Hickson 

 that the mere absence of spicules does not make a new species. 



Oui- general conclusion is that fvirther investigation will show 

 that a number of species of Clavularia should be merged in one, 

 and that at present attention should be paid to the ' tout ensemble ' 

 of characters rather than to any single peculiarity when that is of 

 a quantitative nature. 



These remai'ks may serve to support our impression that some 

 of the species of Clamdaria are in a state of flux, but they 

 may also suggest an inquiry as to the justifiability of adding- 

 seven new species to the already lengthy list. The general answer 

 is supplied by the descriptions given ; the characters of the new 

 species seem to exclude the possibility of referring them to any of 

 the species known to us fi'om previous memoirs. 



It may be useful, however, to indicate briefly some of their 

 outstanding features : — 



C. crosslandi has characteristic exceedingly minute spicules like 

 water- worn sand-graiiis and they are crowded in eight longitudinal 

 white ridges. 



C. repens is like the well-defined C. margaritiferce, but has very 

 dififerent spicules — minute capstans and some qviadrangular forms 

 with an axial cross. 



(7. pulchra has unusually long polyps, tentacles, and pinnules. 



C. zanzibarensis has 6-8 rows of wart-like pinnules practically 

 covering the short blunt tentacles, and the colour is peculiar. 



C. mollis has grouped polyps, thread-like pinnules almost 

 covering the tentacles, and an unusual amount of contraction. 



C. paj'vida has very unusual tentacles with only 9 pinnules on 

 each side, though certainly mature, as the eggs and embryos show. 



C. pregnans has short conical pinnules all round the tentacles 

 and a very large genital expansion with embiyos. 



We may also call special attention to the viviparity I'eadily 

 demonstrable in G. pregnans and also apparent in G. parvida. 



"Very noteworthy in some of the species is the profuse abun- 

 dance of zooehlorellse. 



