xcii NATURAL HISTORY. 



this part is white, curved over the head, and directed forward ; the eyes are small and 

 white. The tenth segment of the body has only five spines ; the fourth and fifth 

 caudal segments having three, and the others only two spines. 



The femora of the three posterior pairs of legs are each armed with two strong 

 spines posteriorly, of which those on the last are the largest and strongest. The two 

 posterior caudal segments are each furnished with a double styhform process, of which 

 the anterior is the longer. The middle plate of the tail is tmncate, with two styliform 

 processes, similar to those of the preceding genus. 



Plate B, fig. 4, represents a large-sized specimen of the Acanthosoma Hj/strii. 



Figs. 5 and 6, a magnified view of the two anterior pairs of legs. 



Fig. 7, the three posterior segments and middle plate of the tail, together with the 

 lateral and terminal styliform processes. 



MOLLUSCA— CEPHALOPODA. 



Nov. Gen.— ROSSIA. (Owen.) 



A single specimen of a small species of Cephalopoda was taken near the beach at 

 Elwin Bay, Prince Regent's Inlet, on the 29th of August, 1832. It was preserved in 

 spirits, and brought to England ; and I am indebted to the friendship of Mr. Owen, 

 Assistant Conservator of the Museum of the Royal College of Surgeons, for the 

 following account of this remarkable animal, accompanied with illustrations of his dis- 

 sections, which have been engraved by Mr. I. Curtis, F.L.S., Sic. 



J. C. R. 



" Tlie small Cephalopod which you have brought from the Arctic Regions to this 

 country, proves to be the type of a new genus. It differs from Lo/igo and Sepiotciithis 

 in the form, proportions, and position of its lateral fins, and in the extent of its horny 

 dorsal style, or gladius; * in these respects, it bears a closer affinity to Sepiola (Leach); 

 it differs, however, from Sepiola generically in having the anterior margin of the 

 mantle free in the whole of its circumference ; its natural position is therefore intcrme- 



♦ This is the term by which Aristotle designates the horny plate of the Loligines : — " Tij jiiv oiv arjTla, 

 Kai t'i TivBiii Kai. TO) TtvSio hroi; iTi ra iTTepea iv Tif Trpavci tov trw/iaroe, li KaXcvut to /ler ariinov, rb h fiAoc- 

 Sub dorso iirma pars sepia: loligioi ac lolio continetur ; illius sepium, borum gladium vocant. — Hist. Animal,, lib. iv. 

 c. 1. 12rao. Ed, Schneider. 



