ON A NEW GENUS AND SPECIES OE CBUSTACEA. 



183 



Observation ceased at 4.43 p.m. 



No. 3. Aug. ?, 1874. — Observation commenced on one indi- 

 vidual of Z). marginalis, $, at 2.31 p.m. 



Eose at 2.56 for 35 sees. 

 » 3. 8 „ 90 „ 



Eose at 3.42 for 3 sees. 

 „ 3.46 ,. 65 „ 



Observation ceased at 4.11. 



Totals 



309 



24 



1338 



Summary. — The female of D. marginalis, rose, on the average, 

 once in about 12g minutes for breathing, and remained, on an 

 average, about 55| seconds at surface for each respiration. The 

 longest interval it was observed to pass without breathing was 

 32| minutes. The duration of a respiration was from 3 seconds 

 to 280 seconds. And the time it was exposed bore to the time 

 it was quiescent a ratio of 1 : 13|^. 



On Actceomorpha erosa, a new Genus and Species of Crustacea. 

 By Edwaed J. MiBRS, F.L.S., Assistant in the Zoological 

 Department, British Museum. 



[Eead December 21, 1876.] 

 (Plate XIY.) 



The remarkable Crustacean here described was brought up by the 

 dredge from a depth of 7 fathoms with a number of other small 

 Crustacea, chiefly Gancroidea. On account of its small size and 

 external resemblance to certain species of Gancridce^ its true posi- 



