A REVIEW OF THE MYSIDACEA 137 



Occurrence. — California : Albatross station 4400, 1 male, 2 females, 

 and the anterior ends of 2 additional females, 18 mm. (type lot) . 



Distribution. — Known only from the type-lot specimens collected 

 off the coast of California in 500 to 507 fathoms. 



Remarks. — This species is distinguished from all other known species 

 of the genus by the combination of characters given above. The ocu- 

 lar plate with its smooth margins and long spiniform process at each 

 anterolateral angle is unique. In the absence of a terminal lobe to the 

 antennal scale projecting beyond the terminal spine of the outer 

 margin, this species differs from all other northern species of the genus 

 except P. calloplura, P. nanum, and P. berkeleyi, and from these species 

 the form and armature of the telson will form a ready means of dis- 

 tinction. The antennal scale and the telson recall those of the genus 

 Michthyops, but P. oculospinum has fully developed biramous pleo- 

 pods in the male and the ocular plate is strongly dissimilar to that 

 found in the genus Michthyops. 



Genus CAESAROMYSIDES Colosi 



Caesaromy sides Colosi, 1916, p. 136. 



CAESAROMYSIDES LIGURIAE Colosi 



The records of this species are given on page 244. 

 Genus MICHTHYOPS Tattersall 

 Michthyops Tattersall, 1911b, p. 60. 



MICHTHYOPS PARVA (Vanhoffen) 



Pseudomma parvum Vanhoffen, 1897, p. 199; 1907, p. 508, pi. 20, figs. 1-3. — 

 Zimmek, 1904, p. 439 ; 1909, p. 104, figs. 208-210.— Hansen, 1908a, p. Ill, pi. 5, 

 figs. 4a-h. 



Michthyops parva Tattersall, 1911b, p. 60. — Stephensen, 1913, p. 76. 



Occurrence. — East coast of United States : Albatross station 2095, 

 1 male; 2195, 2 males; 2215, 1 male; 2229, 1 male; 2230, 1 male. 



Distribution. — Known hitherto from Greenland and from the west 

 coast of Ireland, this species is now recorded for the first time from the 

 western Atlantic slope off the east coast of the United States. Here 

 again we have a member of the boreal fauna that penetrates southward 

 into the Atlantic on both sides where suitable conditions prevail. Its 

 bathymetric distribution is interesting. Off the west coast of Green- 

 land it occurs in 100 fathoms. Off the west coast of Ireland it was 

 found in 880 fathoms, and the above records from eastern America 

 range from 578 to 1,438 fathoms. The species appears to seek deeper 

 water as it extends southward. It is an interesting addition to the 

 American fauna, though its occurrence there was to be expected. 



