﻿A large Tuhidarian from the Moray Firth. 145 



radial canals, whereas the gonophores of our specimen have 

 no ribs and show no radial canals. For similar reasons, we 

 need not consider either T. asymmetrica, Bonnevie, or 

 T. ohliqita, Bonnevie, which have rudimentary tentacles on 

 the gonophores. 



Is it then possible that the Moray Firth specimen is 

 simply a very large and luxuriant representative of the 

 common T. indivisa, perhaps like the vaguely known 

 T. gigantea of Lamouroux, which attained a height of 12-15 

 inches, and was regarded by AUman as "probably only a 

 large form of T. indivisa " ? If the radial canals are absent 

 from the gonophores of the Moray Firth specimen, as they 

 appear to be, then it cannot be identified with T. indivisa, 

 whose gonophores have four radial canals ; but it seems 

 undesirable to press this point, since our specimen has not 

 been adequately fixed. The difficulty of deciding whether 

 our specimen is or is not referable to T. indivisa is com- 

 plicated by the fact that there are considerable differences 

 between Allman's and Hiiicks's descriptions. The real • 

 difficulty is that we cannot judge as to the specific value of 

 numerical and quantitative differences without examining 

 a large number of specimens, which we have not, as yet, 

 been able to do. 



It may be pointed out that the difference between 

 Allman's "40 distal tentacles" and our 76-92 is very 

 considerable, but Hincks simply says " very numerous." 

 Similarly, the difference between Allman's "3 or 4 pendulous 

 racemes of gonophores" and our 14 is also very considerable, 

 but again Hincks says "numerous." On the whole, however, 

 the numerical and quantitative differences seem to warrant us 

 in separating our specimen from T. indivisa, and it seems to 

 us that it should be referred to Boeck's Spitzbergen species, 

 T. regalis. 



In contrasting T. indivisa and T. regalis, Miss Bonnevie 

 notes that the former has 4 radial canals on its gonophores, 

 while the latter has none ; that the former has 20-30 

 proximal tentacles, about 10 mm. in length, while the latter 

 has 20-30, 20-40 mm. in length; that the former has 3-10 

 blastostyles, while the latter has 10-20, 35 mm. in length. 

 VOL. XVII. N 



