1897.] NOTf-MAKINE FATTNA OF SPITSBERGEN. 795 



Some few remarks are added on the most interesting details 

 relative to the rarer forms, whilst brief descriptions are fur- 

 nished for one species, not hitherto described, but which I had 

 previously seen in England, and for one other which it has been 

 necessary to rename. 



Order BDELLOIDA. 



1. Philodina erttheophthalma, Ebr. 



It is with some little doubt that I refer to this species a form 

 which is very closely related to Philodina citrina, and differs from 

 it principally in the size of the mastax (rami, 0*022 mm. lon») and 

 in the shape of the egg (oval, symmetrical and smooth). The 

 species is iuclnded in Bergeudal's list, but it is impossible to affirm 

 that the form seen by him is identical with that now found for 

 although described by Ehrenberg as the commonest of the genus, 

 the species is at the best an unsatisfactory one, the orio-inal de- 

 scription being exceedingly meagre. Gosse has given fuller details 

 of a form which he thought he could refer to it, but these have not 

 been found useful to establish the identity even of the subject of 

 his description. The species has been noted again and again in 

 local lists, but never with any attempt at better definition of its 

 identity. On the other hand, Janson (6), when he wrote his paper 

 on the PMloclincm, had failed to discover any form which he could 

 assign to it, and he rejected it as invalid, and hitherto neither I 

 nor several experienced correspondents have been more successful. 



It would however appear, from the very meagreness of Ehren- 

 berg's description, that the species should be closely related either 

 to P. citrina or to P. roseola, and this postulate is fulfilled by 

 the Spitsbergen examples, which when adult might easily be 

 passed over as P. citrina, varying from the type in lackino- the 

 distinctive colour of that species. Closer examination, however 

 reveals several structural differences (minute, but constant in many 

 examples), of which those mentioned above are themselves suffi- 

 cient to establish specific rank. In young examples the corona is 

 barely wider than the collar, and has a rather smothered appear- 

 ance, which disappears as the animal approaches maturity. In 

 habits it resembles P. roseola, being decidedly restless, and even 

 when feeding it is incessantly changing its position. Erom its 

 behaviour in the trough I judge it to be a "bottom-feeder," and to 

 prefer feeding from a swinging base (as from a mucus thread) 

 rather than from a firm one. 



2. Philodina sp. 



Some specimens with very coarse skin with prominent skin-folds, 

 whose ridges were broken and wrinkled, were referred to a form' 

 recently discovered by Forstmeister L. Bilfinger of Stuttgart, and 

 to be described in a paper now in preparation, 



3. EoTiFER TARDUS, Ehr, 

 A single specimen. 



