﻿144 Proceedings of the Royal Physical Society. 



of gonophores are inserted. They hang down, regularly 

 interpolated, among the proximal tentacles, which they 

 equal in length (12-22 mm.). On several of these pendulous 

 racemes, 48 gonophores were counted. The gonophores are 

 oval in form, with average diameters of 1 mm. and 2 mm. 

 Some of them show a very long spadix, but there is no 

 trace of radial canals. 



The question of present interest is, To which species of 

 Tuhdaria does this magnificent Moray Firth specimen 

 belong ? We may at once dismiss the small species, such 

 as T. larynx and T. bellis, and confine our attention to those 

 which are often or usually over 6 inches in length, namely, 

 T. regalis, Boeck, T. indivisa, L., T. variahilis, Bonnevie, and 

 T. insignis, All man. 



Taking the last first, we find that, according to Allman, 

 the hydrocaulus of T. insignis attains a height of 7 

 inches or more. Indeed, the monographer notes that "it 

 far surpasses in size every British representative of the 

 genus." But the hydrocaulus of our Moray Firth specimen 

 may attain a height of 10 inches. The hydranth of T. 

 insignis (which was found at Dieppe) was about half an 

 inch in height from base to summit, but several hydranths 

 in our specimen originally stood up for nearly an inch. We 

 mention these facts to emphasise the large dimensions of our 

 specimen. We need not, however, delay over T. insignis, 

 for besides difiering markedly as regard its tentacles, it is 

 removed from any close systematic proximity to our 

 specimen by more important differences relating to the 

 blastostyles. In T. insignis the blastostyles are "in six 

 or seven imbricated verticels, with about twenty in each 

 verticel, not pendulous," whereas our specimen has 12 to 

 14 pendulous blastostyles. 



The next on the list is the large T. variaMlis, Bonnevie, 

 which has a height of 100-300 mm., distinct longitudinal 

 striping, 25-35 proximal tentacles (15-20 mm. in length), 

 10-20 blastostyles (20 mm. in length), and is thus in many 

 respects like our specimen. But it again may be left out of 

 account, since its gonophores are characterised by 3-6 high 

 external ribs corresponding to a similar variable number of 



