602 



F. W. GAMBLE. 



Shetlands (Forbes and Goodsir) ; Firth of Forth (Dalyell) ; 

 St. Andrews (Mcintosh). 



Distribution. — Naples (Delle Chiaje), coast of Holland, 

 Germany^ Denmark, Baltic (Droback). 



Planaria atomata has never been described in a sufficiently 

 diagnostic way to render possible the identification of specimens 

 with it. Consequently the above synonymy is very probably 

 incorrect, but it is in no one's power to tell what the authors 

 quoted did mean by their Planaria atomata. Thus Forbes 

 and Goodsir, Fleming, Johnston, and Mcintosh merely give 

 the name and the record. Even those (as Miiller and Oersted) 

 who vouchsafe anatomical facts state the size, the form of the 

 body, the position and arrangement of the eyes, and the form 

 of the penis, and these do not by themselves, signalise a species 

 of Leptoplana. Evidently a fresh and full description of a 

 form is needed, which, if it differs from other existing species, 

 may be called atomata, although its unity with the species of 

 that name can only extend to the points mentioned. Com- 

 parisons with the new fully described atomata would hence- 

 forth be possible. Such a full account of a species agreeing 

 in the form of the body, the position of the eyes, and the com- 

 position of the penis is to be found in Jensen's description 

 ofLeptoplana Droebachensis. 



The small differences that justified Oersted in separating 

 these two species were the following : 



f Leptoplana Droebacl) - 

 ens is, Oe. 

 Lengtli 4 lines. 

 Body "anlice obtuso, deiu sen- 



Oersted 

 (21) 



siiu angustiore. 

 Eyes arranged in an anterior 

 linear clump, and a posterior 

 triangular one of 7. 



Leptoplana atomata, 

 O. F. Miiller. 



Length 3 — 4 lines. 



Body "subovali, poslice an- 

 gustiore." 



Eyes arranged in four clumps. 

 Those of the posterior ones 

 are the larger. 



With regard to the arrangement of the eyes, Jensen's 

 specimens of L. Droebachensis differ from Oersted's just as 

 much or as little as does L. atomata. Oersted does not men- 

 tion a hard penis in Droebachensis, altiiough he describes it in 



