18H7.] PROCEEDINGS OF UNITED STATES NATK^NAL MUSEUM. 155 



i-5"""); (J) by a somewhat different structure of tlie shell, which is 

 marked by pentagoual or hexagonal somewhat elongated meshes ; (3) 

 by the dorsal margin of the head not being constricted posteriorly but 

 l)assing directly into that of the shell ; (4) by the dorsal portion of the 

 shell back of the head being broad and convex, and without any com- 

 pressed sharp dorsal ridge ; aud (5) by the spines on the dorsal edge of 

 the tail being larger and less numerous (about 80), the innermost ones 

 being nearly as broad at base as the rest, &c. 



Mr. Stejueger collected this new species on Bering Island. It has 

 also been obtained by Professor Nordenskiold's expeditions in Greenland 

 aud Waigatsch, and seems consequently to have a considerable range 

 in the northernmost regions of the globe, hence the name which I have 

 proposed above, and which I have already employed in my i)ublic lec- 

 tures on these anin)als. 



Collector's No. 23S4; U. S. iNat. Mus. No. 12432. (Types.) 



4. Calanus cristatiis Ku<")VEii. 



Cdlanus crisiafus H. Krover, in Gaimard's Voyiige en Scaudinavio, Lappoiiio* 

 &.C., Atlas, Zoologie, Criistac('>.s, pl.41, fig. (" iristatus,"erroretypogr.), — 

 S. A. PoPi'K, IJBber die von den Ilerren Dr. Arthur und Anrel Krauso iiu 

 luirdlichen Stilleu Ocean und Ijehringsnieergesammelten freilebeudeu 

 Copepoden, Arch. f. Naturgcseli., L, i, p. 282, taf. xx, fig. l-G. — H Kr()Ver. 

 Naturliist. Tidsskr., 2 Raekke, II, p. .^^46 (184n-4<)). 



I quote the following from Mr. Stejueger'sMS. notes in regard to this 

 species : 



"Quito a nnmber of this species were found at Comaiidor, Bering 

 Island, August 29, 1882, cast ashore during the heavy gale which 

 raged during my stay at that place. After another heavy gjile I found 

 them on the 7th of May, 1883, in enormous nunibers on the sandy 

 beaches south of the main village. From the mouth of Kamennaja 

 River southward for a distance of 1.} kilometers the whole beach was 

 margined with three undulating belts of these animals, which marked 

 the outlines of the waves of the retiring tide. When fresh the animals 

 were semitranslucent and of a rosy flesh-color, but after having been 

 dry for a little while they assumed a vivid orange-red color, which made 

 them very conspicuous on the brownish sand. By actual counting 1 

 found them to average 75 to the inch, which gives a grand total for 1.^- 

 kilometers of nearly 4^ millions. But from the point where I ended my 

 walk I could still see the red lines continuing southward, and have no 

 doubt that they reached at least 10 kilometers further, w^hich would give 

 a total number of no less than 35 millions." 



Kroyer obtained this species from the Kamtschatkan Sea, so that it 

 seems to be peculiar to, the northern part of the Pacific Ocean. 



Collector's Nos. 1507, 2013 ; U. S. Nat. Mus. Nos. 12433 and 12434. 



5. Diaptomus ambiguus, sp. nov. 



The female only. Length, 1.75 """. Particularly remarkable for having 

 the first caudal segment ("abdominal segment ") more than three times 



