REPORT ON THE CRUSTACEA MACRURA. 285 



which the smaller branch lodges. Externally this genus closely resembles Philonicus, 

 from which, how T ever, it may be readily distinguished by having a small tooth on the 

 margin of the carapace corresponding to the outer side of the second pair of antennae, 

 and a small tubercle on the inner side of the ophthalmopod ; by the ophthalmopod being 

 single-jointed ; by the length of the second pair of gnathopoda and of the last two pairs 

 of pereiopoda ; by the absence of a basecphysis, how T ever rudimentary, on any of the 

 appendages of the pereion posterior to the gnathopoda, and by the presence of rudi- 

 mentary podobranchial plumes on the mastigobranchial plate of the second pair of 

 gnathopoda and the first pair of pereiopoda. 



Geographical Distribution. — The range of this genus is known only from the habitats 

 of a few species ; one from the Mid-Atlantic, and the others from the Mid-Pacific and the 

 Polynesian Seas, and all from extremely deep water. 



Haliporus equalis, n. sp. (PI. XLI. fig. 1). 



Eostrum in the male slightly elevated from the base, horizontal in the female, smooth 

 below, fringed with long hairs, armed on the upper surface w T ith nine teeth, six sharp, 

 equally distant, and tw r o on the gastric region. Both hepatic and antennal regions are 

 furnished with four teeth ; the second tooth, corresponding to the antenna, is situate behind 

 the margin. Pleon smooth, laterally compressed. Last two somites dorsally carinated, 

 the posterior terminating in a small but distinct tooth. Telson shorter than the inner 

 branch of the rhipidura. 



Ophthalmopod short, the ophthalmus orbicular and much larger than the diameter of 

 the stalk. 



The first pair of antennas has a prosartema that is shorter than the ophthalmopod, 

 and a stylocerite that extends beyond the outer angle of the first joint. The flagella 

 are long and slender, equal in length to the entire animal. 



The second carries a scaphocerite that extends beyond the extremity of the distal 

 joint of the peduncle of the first pair, and terminates in a flagellum that is about twice 

 the length of the animal. 



The anterior three pairs of pereiopoda are rather short ; the posterior two are very 

 long and slender. 



Length, of both male and female, about 63 mm. (2'5 in.). 



Habitat.— Station 200, October 23, 1874; lat. 6° 47' N., long. 122° 28' E.; between 

 the Philippine Islands and Borneo ; depth, 250 fathoms ; bottom, green mud. Seven 

 specimens ; females. 



Observation.— This species very closely resembles Penmus crassicornis, Milne- 

 Edwards, but it may readily be distinguished by the eye being larger and the peduncle 



