Crustacea.] 



SUBANTARCTIC ISLANDS OF NEW ZEALAND. 



635 



marked in the older and larger specimens. The structure thus formed at the end 

 of the merus is, however, much less marked than in the large specimens that I have 

 referred to the two species 0. serrulata (Dana) and 0. hollonsi, sp. no v. 



In this species, as in 0. serrulata and 0. hollonsi, the carpus of the fifth peraeopod 

 bends outwards on the merus so that when bent it lies almost at right angles to the 

 general longitudinal line of the body ; it then rests on the ground, and the spinous 

 processes on the end of the merus can be pressed into the sand, and the animal is 

 thus enabled to stand firmly when walking or preparing to leap by suddenly extend- 

 ing the pleon. 



Orchestia hollonsi, sp. nov. 



Male. — In general, like 0. serrulata, but with all segments of the body quite 

 smooth ; the third pleon segment with the hind margin serrate and provided with 

 short setae, the posterior angle a right angle or a little produced. The second an- 

 tennae only about one-third the length of the body. The second gnathopod (fig. 66) 

 with propod greatly enlarged, palm some- 

 what oblique, defining-tooth long and acutely 

 pointed ; a round prominence on the palm 

 towards the base of the finger, from which 

 it is separated by a slight depression ; from 

 this prominence the palm proceeds almost 

 straight towards the defining-tooth, but is 

 separated from it by another narrow depres- 

 sion ; a few short setae along the borders 

 of the palm ; the finger somewhat curved, 

 with a very slight enlargement opposite the 

 middle of the palm. Fifth peraeopod (fig. 6c) 

 with the posterior expansion of the basos 

 somewhat narrow, the posterior margin ob- 

 scurely serrate and usually somewhat con- 

 cave about the middle, the lower angle 

 produced downwards into an obtuse lobe 

 reaching considerably beyond the end of the 

 ischium, the margins of this lobe being obscurely serrate like the posterior margin ; 

 merus with the distal end deeply hollowed, the anterior angle produced into a long 

 sharp tooth curved inwards, posterior angle broader and less produced ; carpus 

 about as long as the propod but considerably broader ; a few short setae present 

 on the merus, carpus, and propod. 



Female. — First gnathopod similar to that of 0. serrulata, but with the propod 

 slightly enlarged at its distal end; the fifth peraeopod not showing the special 

 characters described in the male to the same degree. 



Length of largest specimens, about 28 mm. 



Hob. — Bounty Islands, under guano (Dr. L. Cockayne, July, 1903) ; Snares 

 (Chilton, 11th November, 1907) ; Ewing Island (J. B. Mayne, November, 1907). 



Type in the Canterbury Museum, New Zealand. 



It is only with great hesitation that I propose this new species ; but the speci- 

 mens from Bounty Island are specially large and well marked, and, as they are the 

 first Orchestia gathered from that island, it may cause less confusion to give them a 



Fig. 6. — Orchestia hollonsi, sp. nov. 



6a. First gnathopod of male. 

 66. Second gnathopod of male. 

 6c. Fifth peraeopod of male. 



