CHONDRACANTHUS ORNATUS. 183 



position of these lateral tubercles seems to vary 

 slight! y in different specimens. Abdomen exceedingly 

 small and inconspicuous. Egg-strings of moderate 

 length and stoutness, like those of Chondracanthus 

 limandse. 



The size of the more typical of the female specimens 

 observed is as follows : from the forehead to the 

 posterior end of the body 5 mm., from the forehead 

 to the end of the egg-strings 11 '5 mm., the width of the 

 genito-thoracic segment at the posterior end about 

 equal to the length, so that, as already stated, the 

 body of the animal has a general outline closely 

 similar to that of an equilateral triangle. 



Male. The male is very small, measuring scarcely 

 half a millimetre in length ; it is of a robust form 

 and does not differ very much from the male of 

 Chondracanthus cornutus. 



Habitat. Parasitic on the gills of spotted dragonets 

 (Callionymus maculatus Bonap.). Firth of Clyde, 1899 

 and 1901 ; Moray Firth, 1900. 



Though Chondracanthus ornatus is of a tolerably large size, 

 it is so well concealed that it easily escapes notice, and it is 

 only by turning back the gill-covers that the observer can 

 be sure whether the parasite is present or not. Hitherto 

 this Chondracanthus has only been obtained on the spotted 

 dragonet, and frequently it has been found associated with 

 another species the Hzemobaphoides ambiguus (T. Scott), pre- 

 viously described. As pointed out in the description of Hsemo- 

 baphoides, the two species sometimes occurred on the same 

 fish, on opposite sides or on the same side ; occasionally also 

 a Chondracanthus would be found on one side and a H&mo- 

 baphoides on the other. The Chondracanthus was usually of 

 a purplish colour tinged with brown. About 14 per cent, of 

 the fishes examined were found to harbour the Chondra- 

 canthus. 



Genus 37. MEDESICASTE Kroner, 1863. 



Syn. Chondracanthus Auct. ; Lernentoma Baird ; Oralien Bassett-Sinith. 



This genus was established for the reception of a 

 Chondracanthus which, though agreeing in some 



