436 DR S. F. HARMER AND DR W. G. HIDEWOOD ON THE 



In six individuals of C. hodgsoni which were partially dissected and in which ovaries 

 could be identified with certainty the results were somewhat less uniform. Two of 

 these zooids had ten arms each ; 1 had eleven ; and 3 had twelve arms. But even 

 here there is a sufficient amount of correspondence with the results arrived at by 

 ANDERSSON to give some support to the conclusion that C. ingequatus is synonymous 

 with C. hodgsoni, on the assumption that the number of arms is not invariable. 



CffiNCECIUM. 



It can hardly be doubted, from the published figures, that there is at least a consider- 

 able resemblance between the coenoecium of C. hodgsoni and that of C. insequatus. 

 ANDERSSON'S figure (07, pi. ii. fig. 1) of the latter closely resembles RIDEWOOD'S (07 1 , pi. ii. 

 fig. 1) of the former. It may be noted that both figures represent the natural size of 

 the object. In both cases the general appearance of the coenoecium and its mode of 

 branching are substantially the same ; and the same result is arrived at by a comparison 

 of the actual specimens. RIDEWOOD states (p. 51) that the spines are simple, forked, or 

 trifid, and that the length of their free part is variable, usually within the limits 5 to 

 15 mm. ANDERSSON states (p. 10) that the length of the " Ausliiufer," by which we 

 understand the free parts of the spines, may reach 20 mm. ; and (p. 19) that they may 

 be divided into two or three branches. Although this latter statement is made in a 

 paragraph which refers to two other species as well as to C. in&quatus, an inspection 

 of his figure shows that it really refers to the species under consideration. 



We may add that the comparison of the actual specimens shows that C. ingequatus 

 resembles C. hodgsoni in general size and proportions of the colony, in the colour of the 

 ccenoecium, and in the length and thickness of the spines. In both forms the ostia are 

 elliptical and their average long diameter is 3 mm. ; while in both the number of spines 

 associated with each ostium is about four or five. 



MEASUREMENTS OP ZOOIDS. 



According to RIDEWOOD (07 1 , p. 53), the zooids of C. hodgsoni measure about 2 mm. 

 from the caecal end of the body to the dorsal border of the proboscis. ANDERSSON 

 (07, p. 10) gives the length of a zooid of C. ingequatus which is not too strongly 

 contracted as about 3 mm. It must be remembered, however, that no special care had 

 been taken, in preserving the Discovery material, to obtain well-extended zooids ; 

 and that ANDERSSON had the opportunity of examining the zooids of the form described 

 by him in the living condition. It is, moreover, not quite clear how his measurement 

 was taken. 



We have ourselves measured several zooids of both forms in more or less median sagit- 

 tal sections, the measurement being taken in each case from the extremity of the caecal 

 end of the metasome to the dorsal border of the proboscis. According to these measure- 



(EOY. soc. EDIN. TRANS., VOL. XLIX., 562.) 



