"Scotia" Collections. On Echinorhynchus antarcticus, n. sp., and its Allies. By 

 John Rennie, D.Sc., University of Aberdeen. Communicated by WM. S. BRUCE, 

 Esq. (With a Plate.) 



(Read March 5, 1906.) 



The form described in the present paper was found amongst the contents of the 

 stomach of a Weddell seal (Leptonychotes weddelli), taken by the Scottish National 

 Antarctic Expedition in Scotia Bay, South Orkneys. In all about sixty specimens were 

 collected. They occurred unattached amongst material in a semi-fluid condition, so 

 that it is not possible to state definitely whether the seal or some animal upon which it 

 fed is the normal host of this parasite. This question, however, in the case of the 

 Echinorhynchi, appears from the work of de Marval * to be one of minor importance. 

 He has shown that in the Echinorhynchi of birds there is a most marked absence of 

 specialisation of hosts, and quotes from other authors various instances of the same 

 parasite occurring in different vertebrate classes. The worms in the present case 

 showed no indication of having been affected by the digestive juices of the seal. As 

 will appear from the description given below, their structural peculiarities suggest 

 relationships with certain forms known to inhabit aquatic birds. 







External Features. 



The most-striking peculiarity in the structure of this parasite is its external form. 

 This has a marked resemblance to an ordinary pipe with a very short stem and 

 adorned with a somewhat fantastic lid (fig. 1 ). Three regions are distinguishable the 

 rostrum and two body-divisions. Of these, the anterior bears spines regularly 

 distributed over its whole surface ; the posterior is spiny only in part. The former 

 further differs in shape, being disc-like ; the latter is partly bowl-shaped, partly 

 cylindrical. The worms are of small size. The following dimensions of four specimens 

 may be regarded as typical : 



No. I. II. III. IV. 



Total length of body 5-25 4-3 3-30 4-3 



Diameter of widest part (anterior spiny region) . . 2'00 2'5 2'05 2-3 



Vertical height of anterior region .... 1'75 1'6 1'9 2'0 



Length of cylindrical tail region .... 2'68 2-1 1'2 1'7 



Ratio of tail region to total body-length ... -51 -49 -36 '39 



Numbers 1 and 2, on subsequent examination, proved males, and 3 and 4 females. 

 * Revue Suisse de Zooloyie, tome 13, fasc. 1, pp. 195-387. 



(REPRINTED FROM THE PROCEEDINGS OF THE ROYAL SOCIETY OF EDINBURGH, VOL. XXVI., PP. 437-446.) 



