GARSTANG : RELATIONS OF HESSE S DOTO UNCINATA. Ill 



the posterior truncation of the foot, are most unusual characters, 

 and are at once sufficient to indicate the natural position of the 

 species within the genus Hancockia. 



The distinctive features of the few recorded specimens of 

 Hancockia ( = Govia) have recently been tabulated in a most useful 

 manner by Mr. Gamble,* and the smaller details are to be gained 

 from the original papers of Gosse, Trinchese, and Gamble 

 already cited. Hancockia uncinata (Hesse) apparently agrees with 

 H cudactylota (Gosse) in possessing a greenish epidermis, for this is 

 the probable interpretation of the "clear green borders" which 

 Hesse ascribes to the oral and pleuropodial papillae in his specimens 

 — a probability rendered very strong after a glance at the original 

 figures. But H. uncinata differs from H eudadylota and from 

 H. viridis (Trinchese), and agrees with H. rubra (Tr. ) in the absence 

 of projections from the margins of the rhinophoral sheaths. Moreover, 

 judging from Hesse's description and figures, H. uncinata differs 

 from all the other species of the genus in possessing only three velar 

 processes on each side, in the conspicuousness of the eyes, in the 

 non-lamination of the rhinophores, and in the deep subdivision of 

 the pleuropodial lobes into four close-set finger-like processes. It is 

 possible that the two first of these differences are due to the 

 immaturity of Hesse's specimens. It is also very probable that 

 Hesse has described the rhinophores as simple from his having 

 noticed only the "smooth columnar tips" of these structures, the 

 peculiar basal bulb, which bears the rhinophoral laminae in 

 Hancockia, having been retracted within the sheath. Criticism leaves 

 us, therefore, only the very deeply incised character of the pleuro- 

 podial lobes (see Hesse, pi. xiii., fig. 3) in H. uncinata as unique 

 within the genus. It is impossible at present to say whether even 

 this feature is one of specific value. Mr. Gamble's specimen of 

 H cudactylota (7 mm. long.) comes nearest to Hesse's individuals in 

 point of size, and it is significant that the incisions in the lobes are 

 relatively deeper in his specimen (see his fig. 3) than in the larger 

 individuals figured by Gosse (I.e., figs, f, g) and Trinchese (l.c , 

 figs. 1, 6, 7). For the present, however, it is advisable to regard 

 H. uncinata as a species distinguishable from the others by the 

 character in question, especially as the habits of Hesse's specimens 

 were altogether different from those which have been recorded for 

 the remaining species. The latter have been invariably taken among 

 algae, and seem to have been phytophagous ; while Hesse's 

 specimens were greedily carnivorous, and were taken at Brest in 



Ann Mag Nat. Hist., (6) i.w, 1892, pp. 378-385, Plate xvii. 



