Sir H. H. Howorth—The Western Baltic. 411 



invertebrates from thence we also have Mechisa aurita, Cyanea 

 capillata, Gammarus, and Idotea entomon. 



Let us now move westward. A good test of the poverty of the 

 Baltic in marine life in the longitude of Bornholm is afforded by the 

 following list of the result of a fortnight's careful dredging on both 

 the east and west of the island by a collector employed by Meyer 

 named George Holm, in 1863, and containing a list of all animal 

 forms, living or dead, he came across while dredging, except fishes 

 and Protozoa. (See Mey. & Mob., " Fauna der Kieler Bucht," i, xx.) 



Succinea oblonga. Planaria torva. 



Neritinajluviatilis. Dendroccelum lacteum. 



Rissoa ulvce. Palcemon squilla. 



Fontolimax eapitatus. Crangon vulgaris. 



Litorina litorea. Mysisflexicosa. 



Mytilus edulis. Gammarus locusta. 



Cardium edule. Idotea tricuspidata. 



Tellina solidula. Sphceroma sp. 



Sarcochitimi polyoum. Jmra s'^. 



Piscicola sp. Larvae of Phryganea, and three 



Nereis diversicolor. different kinds of Diptera. 



Spirorhis tiautiloides. 



The shells reported from the sea between Moen, Stevns, the south 

 coast of Skane, Bornholm, and Eugen are : — 



Utriculus obtiisus. Macoma [Tellina) calcarea. 



Eydrobia ulvce. M. balthica. 



Litorina rudis. Cardium exiguum (var.). 



Astarte borealis (? elliptica). C. edule. 



A. compressa. Mytilus edulis. 



My a arenaria. 



(Petersen, " Om de Skalbarende Mollusken udbredningsfolhold 

 i de Danske haven, etc.," p. 42.) 



According to Munthe, the two species of Astarte from this part of 

 the Baltic, which he identifies as A. borealis and A. elliptica, are of 

 diminutive growth, and live there therefore under unfavourable 

 conditions. There cannot be any doubt, he adds, that they migrated 

 to the Baltic after the Ancylus time (Bull. Geol. Inst. Ups., ii, 

 pp. 14, 15). Litorina litorea, according to Munthe, also occurs in 

 the Rugen waters, while Scrohicidaria piperata and alba are reported 

 from the mainland opposite Rugen at Greifswald. K. Brandt says 

 that to the east of Rugen there are no sponges or Tunicates, only 

 one Bryozoan, namely, Membranipora pilosa (var. membranacea), 

 and one Cirripede, i.e. Balanus improvisiis. 



The straits between Gjedserode, in the island of Falster, and 

 Darsserort, on the mainland of Mecklenburg, seem to form a con- 

 siderable barrier to the eastern migration of submarine forms, and 

 west of the straits the life becomes decidedly richer. 



In 1889 Dr. Max Braun published a paper on the fauna, except 

 the Polyzoa, of Wismar harbour in the Archiv Nat. Hist. Soc. 

 Mecklenburg. In this he gives, inter alia, a list of the mollusca 

 which had been found there, as follows : — 



