NO. 2286. TUB NEW VOPEPOD fAMILY SPEYRI I DAE— WILSON. 571 



49759. U.S.N.M), from Sebastes marinus taken off Cape Cod in 

 1879; a single female with attached male (Cat. No. 497G0, U.S.N.M), 

 from iVanafonnms (joodei taken off the New Jersey coast by the Al- 

 batross in 1884; four immature females (Cat. No. 49761, U.S.N.M), 

 from the same host and locality in 1885 ; a single female, lacking the 

 hammer, from Haloporphyrus viola, cleared to show the internal 

 anatomy. 



Specific characters of female. — Cephalothorax enlarged by lateral 

 processes until it is usually a little wider than the genital segment. 

 In young females and in some matiu'e ones the outer ends of the 

 processes are bluntly pointed, giving the hammer a transversely ellip- 

 tical outline, with rather pointed ends. In other specimens the ends 

 of the processes are enlarged into knobs and one or both of the knobs 

 may be bifid, giving the creature much more of a hammer shape. 

 Owing to torsion the transverse diameter of the head in matured 

 females is usually at right angles to that of the trunk. Kr0yer, who 

 founded the species, claimed that this enlarged portion was the head 

 alone, but most of the other observers have called it a cephalothorax, 

 which it is now definitely proved to be by the presence of swimming 

 legs in immature specimens. This cephalothorax is followed by a 

 narrow neck of varying length, but fully as long in the young females 

 as in the older ones. Then comes an enlarged trunk made up chiefly 

 of the genital segment, which is more or less heart-shaped and 

 strongly flattened dorsoventrally. To it are attached a pair of anal 

 laminae and a pair of posterior processes, simple at first but becoming 

 more and more profusely branched as the animal matures. 



In the youngest specimen obtained (fig. 15.) the lateral lobes of 

 the cephalothorax are small, not pointed, and plainly thoracic in ori- 

 gin; the head projects from the ventral surface and is scarcely visible 

 in dorsal view. The walls of the entire body are of equal thickness 

 and perfectly transparent like glass; the neck is very slender but is 

 25 mm. in length and of uniform width; the trunk is an elongated 

 oval, five times the diameter of the neck ; the abdomen is fused with 

 the genital segment, but is well differentiated by breaks in the muscu- 

 lature and by lateral sinuses at its base ; the posterior processes arise 

 from its dorsal surface and are simple and unbranched, but somewhat 

 flattened dorsoventrally. 



Inside of the trunk the filiform intestine increases gradually in 

 diameter and is then contracted again into a barrel-shaped rectum 

 about one-fourth the distance from the posterior end. Along the 

 enlarged portion can be seen the beginnings of the intestinal processes, 

 which assume the form of two rows of small Imobs on either side, one 

 dorsal and the other ventral, and a single row along the center of the 

 dorsal surface. 



