collected in the Sea of Spitzbergen. 59 



thinner proboscis is lo niillinis. lonjc^. Tlu' smooth suiface is 

 ot" a pearl-^rey colour, witli taint yellowish pifj^nient-spots. 

 On the intestine I found three suspensors, whilst Keferstein 

 gives only one, and moreover the convolutions of the intestine 

 were twiste<l round one of the retractors — a character which is 

 probably to be regarded as a malformation caused by disturb- 

 ance of development. The species was previously known only 

 from ( rrecnland. 



Halicryptas spinulosus (V. Sieb.). Stortjord. 



The occurrence of this animal in the sea of Spitzbergen 

 was made known by a note of Keferstein's (Zeitschr. fiir wiss. 

 Zool. 18G5, XV. p. 441), who saw large specimens, collected 

 by Malmgren, in the ^luscum of Stockholm. As, to my know- 

 ledge, the worm has never been found in the North Sea ; but 

 its occuiTence beyond the Arctic Ocean is limited to the Baltic 

 (Reval, Riga, Danzig, liiddensee, and the harbour of Kiel), 

 there appears to be a similar condition for its distribution as 

 for that oi Antino'e Sarsii^ except that the Ilalicryptus occurs 

 also in the southern part of the Baltic, where Antinoe Sarsii 

 is wanting. That Ilalicn/ptus is consequently to be regarded 

 as an originally widely diffused inhabitant of the Northern 

 Ocean, which has been displaced from the Norwegian coast, 

 since the glacial period, by the invasion of the gulf-sti'eam, 

 but has maintainea its existence in the Baltic, may probably 

 be affirmed, although its distribution cannot be accepted as a 

 proof that the icy sea was formerly united Avith the Baltic 

 through the White Sea and Ladoga Bay ; for as it occurs also 

 in the southern part of the Baltic, it cannot be denied that the 

 combination of Baltic and Spitzbergen forms may have taken 

 place, in the glacial period, through water-passages, such as 

 the Sound and the Belt, wdiich now unite the North Sea and 

 the Baltic. But this renders more remarkable tlie peculiar 

 dli>tr\hution of A^itiuoe Sarsii, the Baltic forms of Avhich, as 

 above mentioned, are so shut off in the Baltic that their dif- 

 fusion cannot have taken place in this way. Sanger has 

 stated (according to Leuckart's Report on the Progress of the 

 Natural History of the Lower Animals in 1868-69, in Arch, 

 fiir Naturg. xxxv. part 2, p. 281) that the Halienjpti of the 

 Bay of Kiel and those occiu-ring near Danzig and Reval ex- 

 hibit differences in the oesophageal teeth, the Kiel variety 

 having 8 series of oesophageal teeth each w^ith 8-12 lateral 

 teeth, and the Danzig variety only 5 series of oesophageal 

 teeth, each with 4-8 lateral teeth. We do not know whether 

 differences in the general size of the animals are combined 

 with this. It would be interesting to ascertain whether local 

 races have been developed in this case, and in what propor- 



