146 



Part III. — Eighteenth Annual Report 



Fam. Ergasilioe. 



This family has apparently only two, or at most three, genera belonging 

 to it, but the number of species is about twenty-two. All the species are 

 small and easily overlooked. I have notes of two species each of which 

 represents a separate genus. 



Genus Bomolochus, JS r ordmann (1832). 



Bomolochus solece, Claus. 



1864. Bomolochus solece, Claus, Zeitschrift fur Wissenschaft. 



Zool., vol. xiv., p. 374, PI. XXXV. 

 1893. Bomolochus solex, T. Scott, Eleventh Ann. Rep. Fish. 



Board for Scot. (III.), p. 212, PL V. 



This copepod is found occasionally on the back of the common sole, 

 Solea vulgaris. Those I have observed were on the coloured side, and were 

 not easily noticed. It is a species that may readily escape detection, and 

 may therefore be more frequent than it at present appears to be. I have 

 found Bomolochus solece on Solea vulgaris captured near Grimsby, and 

 also on the same species of fish captured in the Firth of Forth and in the 

 Firth of Clyde. The specimen described and figured in the Fishery Board 

 Report, referred to above, is from the Firth of Forth. 



Genus Thersites, Pagenstecher (1861). 



Ther sites gasterostei, Pagenstecher. (PI. V., figs. 1-7.) 



1861. Thersites gasterostei, Pagenstecher, Arch. f. Naturg. 



vol. xvii., p. 118, PI. VI., figs. 1-9. 

 1863. Ergasilus gasterostei, Kroyer, Xaturh., Tidsskr., R. 3, 



vol. ii., p. 223, PI. XII., fig. 2. 

 1892. Thersites gasterostei, Canu, Copep. du Boulonnais, p. 245, 



PI. XXIII., tigs. 13-18. 

 1899. Ergasilus gasterostei, Basset-Smith, Proc. Zool. Soc. 



London (April 1899), p. 444. 



Description of the Female. — The cephalothorax is considerably dilated 

 on the dorsal aspect, so that when viewed from the side or from above it 

 appears to be almost spherical; abdomen short (fig. 1). The specimen 

 represented by the figure carried two ovisacs, which were large in 

 proportion to the animal. 



The antennules (fig. 2) are very short, moderately stout, and five- 

 jointed; the two end joints are each rather shorter than any of the other 

 three, and they are all sparingly setiferous ; the formula shows approxi- 

 mately the proportional lengths of all the joints — 



Proportional lengths of the joints?, 16 • 10 • 11 • 7 • 8 

 Numbers of the joints, 1 • 2 ■ 3 • 4 • 5 



The antennae are short and stout, and are each j^rovided with a strong 

 terminal claw (fig. 3). 



The mandibles appeared to have a bilobed-pectinated biting part, but 

 owing to the structure of the Copepod these organs were somewhat 

 difficult to dissect out ; the maxillse were also somewhat obscure. 



The anterior foot-jaws (1st maxillipedes) are simple, and provided with 

 one or two small seta?. The posterior foot-jaws (2nd maxillipedes) have 

 an enlarged basal part to which is articulated a more slender curved arm 

 bearing a few strong apical spines (fig. 4). 



