172 



Part III — Fifteenth Annual Report 



SOME PARASITES OF C ALAN US FINMARCHICUS. 



First. 



Calanus with (?) Microniscus calani, G. 0. Sars (PI. III. fig. 20). The 

 drawing shows a Microniscus in situ on a Calanus, and this is the position 

 in which I usually find the parasite when it happens to be attached to a 

 Calanus ; but the parasite is more frequently obtained free than in the 

 position shown by the drawing, through its having, in one way or other, 

 become detached from the copepod. 



Second. 



Calanus infested by a Nematode parasite (PI. III. fig. 21). This 

 drawing is that of a Calamis, bearing internally a Nematode parasite 

 much longer than its host. It sometimes happens that a considerable 

 proportion of the Ccdani contained in a tow-net gathering will be found 

 infested by these parasites, while at other times the parasites are rarely 

 observed. 



Third. 



Calanus with (?) Infusorian parasite (PI. III. fig. 22). This drawing 

 is that of a Calanus with an Infusorian-\ike parasite adhering to it. 

 Specimens of Calanus are sometimes found with several of these organisms 

 attached to them ; the parasites are found adhering to the body of the 

 copepods, to the antennules, to the antennae, aud to other appendages, but 

 usually about the head ; sometimes large numbers of Calanus will be 

 found infested by these parasites. 



All these three parasitic forms have been observed in the Clyde, up as 

 far as the head of Loch Fyne, during the past year. 



DESCRIPTION OF THE PLATES. 

 Plate I. 



Delavalia mimica, n. sp. 



Fig. 1. Female, side view, 

 Fig. 2. Antennule, female, 

 Fig. 3. Mandible and Palp, . 

 Fig. 4. Posterior foot-jaw, 

 Fig. 5. Foot of first pair of swimming feet, 

 Fig. 6. Foot of fourth pair of swimming feet, 

 Fig. 7. Foot of fifth pair of swimming feet 

 female, 



Fig. 8. Foot of fifth pair of swimming feet 

 male, (A) Appendage of first ab 

 dominal segment, male, 



Fig. 9. Last abdominal segments and caudal 

 stylets, 



50 diameters 

 507 „ 

 507 „ 

 760 „ 



380 



x 



X 

 X 

 X 

 X 



x 337 

 x 380 



x 380 

 x 253 



