THE HYDROIDS OF THE SCOTTISH NATIONAL ANTARCTIC EXPEDITION. 73 



EucopeUa crenata (?), Havtlaub, 1901. 



A very few examples, whose occurrence has already been mentioned (Ritchie, 1907,'°' 

 p. 488, footnote), were creeping on seaweed obtained on the shore of St Vincent, Cape 

 Verde Islands. The absolute identification of these examples with Professor Hartlatjb's 

 £. crenata is, in the absence of the gonosome, impossible, and, considering differences 

 which occur in the shape of the hydrotheca and in the ringing of the peduncle, 

 appears to me to be a matter of doubt. Our specimens, however, are identical 

 with those described by Dr A. Billard, 1907, and I follow him in assigning them 

 (with a query) to the above species. The hydrotheca are more conical than 

 those of the type, and their proportions differ slightly from those of Billard's 

 specimens, where the depth exceeds the breadth, for here these dimensions are 

 identical, or the latter may even exceed the former. The margin of the hydrotheca 

 is cut into about thirteen rounded teeth, and above the projecting septum at the 

 base there occurs a circle of from 28 to 31 bright dots (indicated in Hartlaub's fig. 27). 

 The peduncles bear from 9 to 12 sharply defined rings at the base, and from 1 to 4 

 annulations at the summit, while the median portion is generally more or less 

 corrugated. 



Measurements : — 



Length of peduncle ..... 1'01-1'98 mm. 



Breadth „ ..... 0-07-0-09 „ 



Depth of hydrotheca ..... 0-32-0-45 „ 



Breadth „ at margin . . . 0-34-0-40 ,, 



Locality. — Growing on seaweed from the shore to the N.E. of Porto Grande, 

 St Vincent, Cape Verde Islands. 1st December 1902. 



Apparent evidences'of regeneration are given by some of the specimens. To mention 

 one example. The hydrotheca is borne on a stem 1'68 mm. in length, but this stem is 

 composed of two distinct portions, a basal section 1'04 mm. long with walls 9m in 

 thickness, of a dark horn colour and deeply stained by eosin. This portion is 

 sharply truncated at the distal end. It is succeeded by a shorter section 0"64 mm. 

 long, with walls only 6m in thickness, clear and transparent and faintly tinged 

 with eosin. It is apparent that the peduncle has been truncated at a particular point, 

 and that from this point the regenerating hydranth has built a new perisarcal 

 protecting sheath which, as one would expect, differs in density from the older 

 portion. It is interesting to note that the regenerated portion has, instead of 

 continuing the smooth character of the old peduncle, assumed the character of a 

 complete peduncle, for it bears four clean-cut rings above its point of origin, these 

 being followed by a corrugated portion, and this by three rings below the hydrotheca. 

 In all the cases examined the regeneration process has reproduced a complete but 

 miniature peduncle. 



TRANS. ROY. SOC. EDIN., VOL. XLVII. PART I. (NO. 4). 10 



