10 PROCEEDINGS OF THE NATIONAL MUSEUM. vol.59. 



biramose; rami of the first pair two-jointed, the endopod very much 

 reduced; rami of the other pairs three- jointed, the endopod a trifle 

 longer than the exopod. Fifth legs reduced to spines just in front 

 of the base of the egg strings. 



Color (preserved material) reddish yellow, deepening into a brown 

 at the centers of the various segments on the dorsal surface. 



Total length, 5.25 mm. Carapace, including third thorax segment, 

 2 mm. long, 2 mm. wide. Genital segment, 1.10 mm. long, 1 mm. wide. 

 Abdomen 1.90 mm. long, 0.30 mm. wide. Egg strings, 1.60 mm. long. 



(lati furcatus, latus, wide and furcatus, furnished with a furca.) 



Remarks. — On comparing this species with others that have been 

 described it shows most resemblance to Kr0yer's species, caudatus, 

 but differs from it in the presence of visible eyes, in the shape and 

 relative proportions of the carapace, fourth and genital segments, 

 in the spiny covering of the abdomen, and in the shape and armature 

 of the anal laminae. The species exilis has a one- jointed abdomen, 

 while the species tenui furcatus has a two- jointed abdomen, relatively 

 very much narrower. In addition the furca of the present species is 

 radically different from that of any others yet described. 



In the letter accompanying these parasites it was stated, " They 

 have become rather serious pests in our aquaria at the marine sta- 

 tion." Breeding in the restricted areas of aquaria, where every 

 nauplius is protected from its natural enemies, and is insured a 

 suitable host upon reaching the proper stage in its development, a 

 copepod parasite that ordinarily would remain rare may easily de- 

 velop into a serious menace. And once established they prove very 

 difficult to exterminate, and furnish another illustration of the old 

 adage, " An ounce of prevention is worth a pound of cure." 



BLAKEANUS, new genus. 



Generic characters of female. — Head and anterior thorax fused 

 and greatly inflated dorsally after the manner of Doropygus and 

 Buprorus. Antennae, mouth parts, and four pairs of swimming 

 legs packed closely together in a furrow along the ventral midline. 

 A pair of curved horns at the posterior ventral corners of the in- 

 flated portion. Fifth segment abruptly narrowed to normal size. 

 Abdomen distinctly segmented. A pair of external egg strings at- 

 tached close together on the dorsal surface of the genital segment. 

 Basal joint of first antennae enlarged into a broad setose hand. 

 Second antennae nonprehensile. Maxillipeds with a stout terminal 

 claw. Male unknown. 



Type of genus. — Blakeanus corniger, monotypic. 



{Blakeanus, to J. H. Blake, one of the pioneers in the United 

 States Bureau of Fisheries, who made many excellent drawings of 



