380 APPENDIX. 



Page 200. Fallasea cancelloides (Cancellus). 



Ganiniarus cancelloides, (jivrdfeldt, Miin. de VAcud. de 6't. Petersbotuy, 

 viii. pp. 287, 288. t. 9. f. 8. 



*S. Loven, Of vers, af K. Vet. Aktid. Fork. 1861, no. 6. p. 287. 



This species agrees very closely with P. Cancellus of this Catalogue, 

 differing only, as far as I can make out, in the greater development 

 of the tubercles upon the first and second segments of the pleon. 



Hah. In the fresh water lakes Vettern and Venern, Sweden ( Widigren, 

 Olofson, Sf Cederstrom) ; in Baikal and Angara, Siberia {Gerstfeldt). 



I am indebted to my friend Professor Kinahan for an opportunity 

 of examining this species, as well as Pontoporeia ajfftnis and Gamma- 

 racantJiHS lorkatus, from the freshwater lakes of Sweden. These, 

 together with Mifsis relicta, Liljeborg, and Idothea Entomon, Linn., 

 have been dredged in the lakes Vettern and Venern by MM. Widi- 

 gren, Olofson, and Cederstrom. 



Page 205. Add another species : — 



1 a. Gammarus fissicomis. 



Gammarus fissicornis, Surs, Oversiyt den Norsk- Arctiske Region fore- 

 homniende Krebsdyr. p. 28. 



" This species may be known by a strong reversed tooth (spina) in 

 the middle of the posterior margin of the first and second seg- 

 ments of the pleon, wanting in the third, but terminating in 

 the fourth and fifth with an acute longitudinal carina produced 

 posteriorly into a strong, erect, triangular, acute tooth (spina), 

 which is largest in the fourth segment. Antennae veiy short : 

 superior two-thirds longer than the inferior, slightly surpassing 

 one-third of the length of the animal ; secondary appendage of the 

 superior antennae unusually large, equalling half the length of the 

 flagellum, and consisting of fourteen articuli. Gnathopoda having 

 strong subcheliform propoda, largest in the second pair. Posterior 

 pair of pereiopoda longest, being nearly two-thirds of the length 

 of the animal." — Sars. 



Page 205. Gammarus Pulex. 



"b 



Professor Westwood, after extended research, has come to the 

 conclusion that the original specific name of our British freshwater 

 species was Ptdex, and not fluviaiilis. The specific names of these two 

 species should, therefore, be exchanged. 



Page 250. Add four other species : — 

 34 a. AmpMthoe latipes. 



Amphithoe latipes, Sars, Oversiyt den Norsk- Arctislie Reyion fore- 

 konmwnde Krebsdyr. p. 20. 



" This'species is known by a carina on the first two segments of the 



