190 MR. LUBBOCK ON SOME OCEANIC ENTOMOSTRACA 



PCECILOPODA. 

 Baculus, n. g. 

 Bactjlus elongatus, n. s. Cephalothorax 4-articiilatus, segmento antico maximo, 

 sequeiitibus brevibus, subaequis. Oculi duo, parvi. Antennae quatuor, posticis pre- 

 hensilibus. Truucus biiccalis magnus. Maxillipedes fortes. Pedes natatorii octo, 

 biremes. Abdomen 1-articnlatura, elongatum. 



The interesting specimen above described is quite unlike any other witli which we are yet 

 acquainted ; but as it bears no eggs, it is impossible to ascertain what is its sex, or whether 

 it is yet mature. If not, it may be a young state of some little-known species ; but 

 unless this is the case, it must, I think, be considered as the type not only of a new 

 genus, but also of a new family. In general form it resembles a constable's staff. It is 

 thickest near the front end, and gradually tapers to the other extremity. 



The cephalothorax is four-jointed; the first segment occupies more than two-iifths of 

 the whole length. The three following segments are small, and rounded at the sides. The 

 eyes are two in number, small, and seated on a mass of pigment. The anterior antennae 

 are short, three- or four-jointed, and clothed with rather long hairs on the front end. The 

 posterior antennae are shorter and stouter. They end in a large claw, which gives them a 

 prehensile character. 



Immediately behind the large suctorial mouth is a pair of jaAvs, the homologies of 

 which I have not been able to determine. 



The natatory feet are eight in number. The abdomen appears to consist of only a 

 single segment ; it is ringed at the sides, and ends abruptly. At the posterior extremity 

 are two small, slightly projecting disks. 



This remarkable species belongs apparently to the Ergasiloidea, and at first sight some- 

 what resembles Monstrilla. Prom this genus, however, it differs altogether in the form 

 of the abdomen, and in the presence of posterior antennae — a character which might seem 

 to indicate a greater afiinity with Ergasiliis. 



Length Tijth of an inch. 



Caught April 9, in S. lat. 0° 30', W. long. 0° 30'. 

 Pl. XXIX. fig. 40, X 30. 



