Deep-sea and Shallow-water Ilydrozoa. 9 



height of about 15-20 centim. or more, closely crowded to 

 form wide dense tufts, the hydrorhiza of which has the form 

 of a rather thin spreading mass of closely crowded entangled 

 filaments of different sizes. Ramuli extremely slender, 

 jointed, arranged in a very variable manner ; on the basal 

 part of the hydrocaulus they are alternate, placed singly, one 

 to each joint, but in such a manner that they do not strictly 

 fall in the same plane ; higher up the stem they are arranged 

 in pairs, the pairs decussating ; while in the larger number of 

 stems this condition is again lost at the upper part by the 

 ramuli becoming placed in threes at each whorl, each three 

 being so placed as to be vertically above or below every alter- 

 nate three, so that a hexastichous arrangement is produced ; 

 these upper ramuli are borne on a long process (of the stem), 

 which is slightly swollen at the base ; one or two short inter- 

 nodes follow this process before the first hydrotheca-bearing 

 interuode, while between the hydrotheca-bearing internodes one 

 long or two shorter internodes are placed. The internodes 

 are very slender and usually much elongated. The hydro- 

 thecse are small and shallow, slightly wider than the general 

 diameter of the ramulus. Nematophores rather variably 

 arranged ; one below each hydrotheca on the same internode 

 and two above it at the lateral margins, two on the intervening 

 long internode or one on each of the replacing shorter ones, 

 and one on each of the short proximal internodes following the 

 process of the stem ; on this process one or two iiematophores 

 are placed singly along the inner side, and one is placed on 

 each side of the swollen base, nearly in the axil of the ramulas ; 

 one nematophore is placed on the stem directly above the point 

 of origin of each ramulus. 



Gonothecge borne singly in the axil of the ramuli, rather 

 short, suboval, and curved, with an oval subterminal orifice. 



If the genus Hippurella as defined by Allman could be 

 maintained, this form would have to be referred to it ; but it 

 seems to me impossible to retain that genus, since the varying 

 position of the ramuli on which it is founded is a common 

 characteristic of Aniennularia, as shown by their earlier stages. 

 In the common British species, A. antennina^ the ramuli are 

 at first arranged alternately, as in Plumularia^ then va. 'pairs ^ 

 before attaining their verticillate condition (Hincks, Brit. 

 Hydroid Zoophytes, vol. i. p. 281). 



The species, in the general arrangement of its ramuli at 

 different parts of its hydrocaulus, recalls the species A. Jiexa- 

 sticha, A. Johnstoni, A. decussata, and A. Janini-, but in 

 essential characters it cannot be confounded with either of 

 them. 



