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BlilTISH PARASITIC C0PEP0DA. 



its dorsal aspect. Genital segment furnished with two 

 pairs of tridigitate appendages on the under side and 

 with three pairs of somewhat similar digitiform pro- 

 longations on the lateral aspect, the posterior prolon- 

 gations being the larger ; these latter appendages 

 surround and nearly conceal the short, stout, and 

 flattened ovisacs; several median processes also occur 

 on the dorsal aspect of the genital segment. 



Antennules short and moderately expanded. An- 

 tennas prehensile and provided with stout terminal 

 hooks. Mandibles and other mouth -appendages 



One of the ovisacs of Chondr acanthus zei. 



similar to those of Chondracanthus cornutus. Thoracic 

 legs indistinctly biramose, and their structure some- 

 what rudimentary. Ovisacs, which are short and con- 

 tain numerous small ova, compressed laterally so as to 

 have a broadly and somewhat obliquely ovate outline ; 

 not extending beyond the ends of the prolongations 

 described above. Colour white tinged with red. 

 Length about 12 mm., but the size somewhat variable. 



Male. — The male of this species does not appear to 

 differ greatly from that of Chondracanthus cornutus in 

 size and structure. 



Habitat. — Parasitic on the gills and gill-arches of 

 the dory (Zeus faber). Polperro, Cornwall (A. M. 

 Norman). Plymouth (Bassett- Smith). Firths of Forth 



