154 Rev. Canon A. M. Norman on British Mysida3. 



fourth, and fifth pairs very small ; outer branch of fourth pair 

 very long, consisting of about seven articulations, wholly 

 devoid of setai and gradually becoming more slender distally. 



1. Gastrosaccus spinifer (Goes). 



1863. Mysis spinifera, Goes, "Crust, decapoda podoph. marina Sueciee 



&c." (CEfvers. K. Vet.-Akad. Hand, xx.), p. 14 (separate copy). 

 1868. Gastrosaccus sanctus, Norman, Brit. Assoc. Rep. for 1867, p. 438 ; 



and 1869, " Last Report Shetland Dredging," Brit. Assoc. Rep. for 



1868, p. 268. 

 1872. Acanthocaris Livingstoniana, G. Sim, " Stalk-eyed Crust. N.E. 



Coast of Scotland" ('Scottish Naturalist'), p. 4 (separate copy), 



pi. iv. fig. B 1-6. 

 1880. Gastrosaccus spinifer, Stabbing, Ann. «fe Mag. Nat. Hist. 



ser. 5, vol. vi. pp. 114 and 328, pi. iii. 

 1882. Gastrosaccus spiniferus, Ozerniavsky, I. c. fasc. i. p. 87, fasc. iii. 



1890. Gastrosaccus sanctus, Meinert, Vidensk. Udbytte af Kanon- 

 baaden, "Hauch's" Togter. Crust. Malacostraca, p. 207. 



Central portion of hind margin of carapace cleft into a 

 number of fringe-like filaments. Fifth segment of jjJeon 

 dorsally terminating in a produced spine-shaped process. 

 Antennules with three strong spines on outer margin of 

 second joint of peduncle, inner margin of third joint without 

 conspicuous setse. Antenna! scale reaching middle of second 

 joint of peduncle of antennules, its apex not extended beyond 

 extremity of spine of outer margin. Telson with six to eight 

 very large spines on margin, the two distal spines not con- 

 spicuously larger than preceding. Inner uropods slightly 

 longer than the telson, having nine to eleven spines on the 

 inner margin. Outer uropods having the apex bluntly and 

 somewhat obliquely rounded, its outer margin with about 

 thirteen to seventeen large closely-set spines, which are ciliated 

 on the distal margins and have their apices of peculiar form, 

 the edge being folded over, as though a cone-like hollow pro- 

 cess was thus formed. 



In the male the third pleopods have the ultimate joint 

 bearing two small spines on the edge and terminating in two 

 equal-lengthed spine-like processes, one of which is ciliated 

 at the edge. Length 20 millim. 



Hah. Shetland {A. M. N.), Banfi" (7^. Edward), Moray 

 Firth {T. Scott), Firth of Clyde {D, Robertson) ; Starcross, 

 Devon {C. Parker): Mus. Nor. Aberdeen {Sim); Whitby 

 {StehUng) ; oflf Bo'ness, Firth of Forth [T. Scott). 



Distribution. Bahusia in Sweden (Z/oyeA?,fide Gqbs) ) Den- 

 mark [Meinert) ; mouth of the Seine [de Kerville) . 



