290 Part III. — Twentieth Annual Report 



second maxillipeds of the form previously described, but it resembles 

 it in the curve being distinctly sigmoid ; a slender seta springs from near 

 the distal end of the inner margin of the first joint, and two small setse 

 from near the middle of the inner margin of the second joint, a very long 

 and slender seta springs from near the base of the terminal claw, and a 

 smaller one from a point a little further forward (fig. 21). 



The thoracic feet are similar to those of the form already described. 



The male differs little from the female except that the terminal claws 

 of the second maxillipeds are more powerful and more evenly curved 

 (fig. 22). 



Habitat. — On the inside of the gill-covers of Onos mustelus (Lin.)— the 

 Five-bearded Rockling — captured in the Firth of Forth in May, and 

 off Kinnaird Head, in 60 to 80 fathoms, on July 24th, 1901. Also on the 

 inside of the gill-covers of a specimen of Onos cimbrius (Lin.) — the Three- 

 bearded Rockling — captured in the Forth estuary in 1892, and from 

 the gills and gill-covers of the same species of fish taken on Bressay Shoal 

 to the east of Shetland, on December 11th, 1901. Both males and 

 females of this Bomolochus were obtained. 



Remarks. — The species just recorded has such a close general 

 resemblance to Bomolochus solea', Claus, that it might easily be mistaken 

 for that species ; the most obvious difference is in the form of the posterior 

 foot-jaws, by the difference in the structure of these appendages the 

 species may be distinguished even without dissection when viewed from 

 the ventral aspect and with the aid of a good light. 



Bomolochus zeugojyteri, T. Scott, (sp. n.). PI. XIII., figs. 23-25. 



Description of the Female. — Length about "84 mm. (about -^ of an inch). 

 The first body segment is equal to rather more than the entire length of 

 the next three, the last thoracic segment is small (fig. 23). 



The antennuls (fig. 24) are moderately stout ; the second joint is 

 equal to about one and a half times the length of the next one ; the third 

 and fourth are sub-equal, while the fifth and last joints, which are also of 

 about equal length, are rather smaller than the third or fourth ; the 

 penultimate joint is only about two-thirds the length of the end one. 

 The armature of the antennules resembles those of the last species. 



The second maxillipeds are short and moderately robust, the terminal 

 claw is feeble, and the curve of the claw is only slightly sigmoid ; a 

 small seta springs from the distal end of the inner margin, while two 

 slender and moderately elongate setse arise from near the base of the claw 

 as shown in the drawing (fig. 25). 



All the other appendages are somewhat similar to the same appendages 

 in the Bomolochus from the Ling. 



Habitat. — About a dozen specimens, most of them females with 

 ovisacs, were found adhering to the back of a small Miiller's Topknot, 

 Zeugopterus punctatus (Bl.). The fish was captured near the mouth of 

 the Clyde estuary in September 1897, but the Bomolochus were not ob- 

 served till March of the present year (1901); and as it had been in alcohol 

 from the time it was captured, and had more than once been transferred 

 from one vessel to another, it is evident that the copepods must have 

 had a firm hold of their host. 



The marked difference in the structure and armature of the second 

 maxillipeds are the principal characters by which this species may be 

 distinguished ; it is also a smaller species than the other two, being little 

 more than half the size of the Bomolochus from the Ling. 



