REPORT ON THE CRUSTACEA MACRURA. 757 



furnished with a stylamblys near the apex, tipped with numerous cincinnuli. The other 

 pleopoda have their branches subequal in length and a little broader than the first, and 

 carry a long stylamblys, that diminishes hi importance posteriorly, attached to the inner 

 margin of the posterior branch, except in the posterior pair, which helps to form the 

 rhipidura. The outer branch of this pair is armed with a tooth on the outer margin, 

 coincident with the diaeresis, and is as long as the telson. 



Observations. — This species was taken associated with Acanthephyra carinata, which 

 it resembles in the extent of the carinated condition of the dorsal surface from the 

 rostrum to the telson, but the outline of the animal is less evenly arched, the pleon has 

 the four posterior somites furnished each with a tooth of equal importance, and the 

 rostrum, although broken off, is more slender at the base and proportionately longer. The 

 ophthalmopoda are more cylindrical and the ophthalmus blacker, larger, and without a 

 complete ocellus. The scaphocerite is not so broad at the base as in Acanthephyra 

 carinata, but terminates in a point that is nearly as sharp. There is not much else in 

 the specimen of specific importance, and if its rostrum be as long as the carapace and 

 equally dentate, this specimen might be taken for a carinated variety of Acanthephyra 

 purpurea, with the teeth on the frontal crest of the carapace a little more closely planted 

 together. 



'& 



Systellasp)is, 1 n. gen. 



Closely resembles Acanthephyra, but differs externally in the orbit being continued 

 to the first antennal tooth and in the absence of a carina on the dorsal surface of the 

 sixth somite of the pleon. The telson is dorsally grooved and terminates in a pointed 

 extremity. 



The ophthalmopoda are large, pyriform, furnished with an ocellus on the posterior 

 surface and stand on long pedicles. 



The scaphocerite tapers to the extremity, the inner division being rounded and the 

 outer point being less conspicuous than in Acanthephyra. 



A strong point or small tooth exists on the anterior margin of the first somite of the 

 pleon, others are on the posterior margin of the fourth and fifth somites, half-way between 

 the dorsal median line and the suture of union with the lateral coxal plates, and a pair 

 of bolder teeth is repeated on the postero-lateral margin of the sixth somite. 



Observations. — This genus is established chiefly on physiological grounds, the ova 

 beiug very much larger and less numerous than in Acanthephyra, and I have frequently 

 observed in closely allied forms that a difference in the size of the ovum means different 

 stages at which the embryo quits the egg. In addition to this there are certain features 

 in the specimen on which this genus is founded that enable us to distinguish it from 



1 nvni't'Khu, to compress ; aa-nii, shield. 



