no. 2065. THE CRUSTACEA EUPHAUSIACEA— HANSEN. 93 



conspicuously more than two-thirds as long as the median lobe. 

 Fig. 1& represents the process-bearing lobes of the left organ of a 

 large male, and in this organ the inner and the median lobes and 

 their large processes are somewhat longer in proportion to the setif- 

 erous lobe than in the organ shown in fig. \h, in reality showing the 

 same length in proportion to the setiferous lobe as in T. longijpes 

 (pi. 2, fig. Id) ; furthermore, the two largest processes of this organ 

 look as if their terminal part is hollowed on the outer side, and the 

 end of ail three large processes is less produced and more convex on 

 the inner side; finally, the auxiliary lobe is slightly more than half as 

 long as the median lobe. 



Length. — The largest female (from station 4426) is 26 mm.; the 

 largest male (from station 3444) is 25.5 mm. long. 



Remarks. — This specimen was established by Holmes on a single 

 specimen, and his description, together with a figure, is good. T. 

 spinifera is easily distinguished from T. longipes by many characters, 

 among which may be mentioned: The absence of a tooth on the 

 lateral margin of the carapace; the subcircular, not constricted 

 eyes; the third joint of the antennular peduncle shorter than the 

 second ; the protruding setiferous lobe at the end of the second anten- 

 nular joint in the male; no dorsal spine on the third abdominal 

 segment; and the spines on the following segments larger than in 

 T. longipes. 



Distribution. — The type was caught near Fort Bragg, California, 

 near lat. 39^° N". The remarks on occurrence and the list of local- 

 ities comprise our total knowledge of the distribution of T. spinifera. 



29. THYSANOESSA INERMIS Krtfyer (?1846). 

 Plate 2, figs. 2a-2d. 



1882. Euphausia inermis G. 0. Sars, Forh. Vid. Selsk. Christiania for 1882, No. 



18, p. 51, pi. 1, fig. 15. 

 1882. Thysanoessa borealis G. 0. Sars, Forh. Vid. Selsk. Christiania for 1882, No. 



18, p. 52, pi. 1, figs. 16-18. 

 1911. Thysanoessa inermis H. J.. Hansen, Bull. l'Inst. Ocean. Monaco, No. 210, 



pp. 8-13 and p. 38. 



Occurrence. — As discussed in the last-named paper, Rhoda (Boreo- 

 phausia) inermis Kr0yer and Thysanoessa neglecta Kr0yer ( T. borealis 

 G. O. Sars) are varieties of the same species; they are frequently 

 clearly distinguished from each other by the structure of the first 

 pair of thoracic legs, but sometimes transitions between both forms 

 are found. Frequently all animals captured at a locality belong to 

 the same form or variety, but sometimes both have been taken in 

 the same haul. In the following fist of the localities in the Atlantic a 

 word on this topic is added at most stations. The specimens from 

 the Pacific are mentioned separately. 



October 12, 13, 17, 1879. Eastport (about lat. 44° 54' N\). Sur- 

 face. It. Rathbun. 5 specimens. (Var. T. neglecta.) 



