of the Families Lophogastiidaj and Euphausiidse. 455 



specific name T. horealis must yield to tlic later name 

 Nematoscelis viegahps, G. O. Sars. 



In 1887 Professor M'Intosli first recorded Thysanoessa 

 tenera, G. O. Sars ( = T. longicaudata^ Kroyer), as British 

 (Ann. & Mag. Nat. Hist. ser. 5, vol. xix. p. 140). 



Lastly, Boreoj)hausia inermis^ Kroyer, was first published 

 as British by Messrs. Brook and lloyle in their paper " On 

 the Metamorphoses of British Euphausiidai " (Proc. Roy. 

 Soc. Edinb. 1888, p. 414). 



Such were the first records of the species of Lophogastridse 

 and Euphausiidge which at the present time are known to live 

 in our seas. As there is no account of them in any English 

 work, and I consequently have specimens frequently sent 

 to me to name, I have thouglit it desirable to write the 

 following notes on this interesting group of oceanic Crusta- 

 ceans, which are found either as surface swimmers or in deep 

 water at some distance from land. 



The descriptions of the families are in great measure con- 

 densed and slightly modified from the works of G. O. Sars. 



Synopsis of Families ^ Genera^ and Species. 



Suborder SCHIZOPODA. 



Legs furnished with exopodites used for swimming. In 

 rare instances the first pair of legs formed for prehension, more 

 usually this pair, as all the remaining legs, are simple. Ova 

 borne below the carapace between the posterior pair or pairs 

 of legs, usually enclosed in a marsupial sac formed by leaf- 

 like processes which are developed from the base of the legs. 



Fam. I. Lophogastridae. 



Maxillipeds robust ; the exopodite imperfectly developed, 

 consisting of a single joint ; the epipodite very large and pro- 

 jecting within the branchial cavity. First legs with ter- 

 minal joint obtusely rounded, and densely hirsute ; remaining 

 legs having a well-developed nail. Branchiae arborescent, 

 complex, the largest branch freely projecting beneath the 

 body, the remaining branches concealed by the carapace. 

 Marsupium composed of seven pairs of plates. Caudal limbs 

 (pleopods) well developed in both sexes. No phosphorescent 

 organs. Inner uropods not furnished with an auditory appa- 

 ratus at their base. Telson very large, in general form 

 as in the Macrura. 



